Electroluminescent materials and methods of manufacture and use

ABSTRACT

Light emitting polymers can include a plurality of arylene monomeric units and a plurality of soft segment units independently selected from soft segment end caps; soft segment side chains coupled to a portion, but not all, of the arylene monomeric units; internal soft segment monomeric units; and combinations thereof. These light emitting polymers can be used in forming electroluminescent devices or other articles.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 10/285114, filed Oct.31, 2002, now allowed, which claims the benefit of U.S. ProvisionalApplication Ser. No. 60/374,044, filed Apr. 19, 2002, which isincorporated herein by reference.

BACKGROUND

Electroluminescent materials can be used to make organicelectroluminescent (OEL) devices such as organic light emitting diodes(OLEDs). There is continuing research and development of materialssuitable for such devices and methods for making the devices. In someinstances, materials can be selected or developed which facilitate oneor more of these methods.

Patternwise thermal transfer of materials from donor sheets to receptorsubstrates has been proposed as one method for forming OEL devices.Selective thermal transfer of organic light emitters for formation oforganic electroluminescent devices has been shown to be particularlyuseful.

SUMMARY OF THE INVENTION

Generally, the present invention relates to electroluminescentmaterials, organic electroluminescent devices, articles containing theorganic electroluminescent devices, and methods of making and using theorganic electroluminescent devices and articles.

One embodiment is a composition containing a light emitting polymer.This light emitting polymer includes a plurality of arylene monomericunits and a plurality of soft segment units independently selected fromsoft segment end caps; soft segment side chains coupled to a portion,but not all, of the arylene monomeric units; internal soft segmentmonomeric units; and combinations thereof. This composition can be usedin electroluminescent devices or other articles.

Another embodiment is a method of making an electroluminescent device orother article that includes selectively transferring the light emittingpolymer from a donor sheet to a receptor.

Yet another embodiment is a donor sheet having a substrate, alight-to-heat conversion layer, and a transfer layer containing thelight emitting polymer.

Examples of suitable light emitting polymers include those havingFormulas I to XVII:

where D₁ and D₂ are substituted or unsubstituted arylene moieties, eachEC is independently a soft segment end cap group, X and Y are cappinggroups, Ar₁ and Ar₂ are independently selected from substituted andunsubstituted C6-C20 arylene, substituted and unsubstituted C2-C20heteroarylene, and substituted and unsubstituted C18-C60 divalenttriarylamines, k, l, m, n, and o are integers in the range of 2 to 1000,q is an integer in the range of 1 to 4, each Z₁ is independently a softsegment side chain, and each T is independently a soft segment moiety.Suitable light emitting polymers also include polymers having FormulasI′ to XVII′:

where R₁, R₁′, R₃, and R₃′ are independently hydrogen, substituted orunsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C20 aryl,substituted or unsubstituted C3-C20 heteroaryl, or substituted orunsubstituted C1-C30 hydrocarbyl containing one or more S, N, O, P, orSi atoms; R₂, R₂′, R₄ and R₄′ are independently substituted orunsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C20 aryl,substituted or unsubstituted C3-C20 heteroaryl, or substituted orunsubstituted C1-C30 hydrocarbyl containing one or more S, N, O, P, orSi atoms; a is independently in each occurrence 0 or 1; each EC isindependently a soft segment end cap group; X and Y are capping groups;Ar₁ and Ar₂ are independently selected from substituted andunsubstituted C6-C20 arylene, substituted and unsubstituted C2-C20heteroarylene, and substituted and unsubstituted C18-C60 divalenttriarylamines; k, l, m, n, and o are integers in the range of 2 to 1000;each Z₁ and Z₂ is independently a soft segment side chain; and each T isindependently a soft segment moiety.

The above summary of the present invention is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The Figures and the detailed description which follow moreparticularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a schematic side view of an organic electroluminescent displayconstruction;

FIG. 2 is a schematic side view of a donor sheet for transferringmaterials according to the present invention;

FIG. 3 is a schematic side view of an organic electroluminescent displayaccording to the present invention;

FIG. 4A is a schematic side view of a first embodiment of an organicelectroluminescent device;

FIG. 4B is a schematic side view of a second embodiment of an organicelectroluminescent device;

FIG. 4C is a schematic side view of a third embodiment of an organicelectroluminescent device; and

FIG. 4D is a schematic side view of a fourth embodiment of an organicelectroluminescent device.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention.

DETAILED DESCRIPTION

The present invention contemplates electroluminescent materials andmethods for making devices from these materials including, but notlimited to, selective thermal patterning of the electroluminescentmaterials onto a receptor. Such methods and materials can be used toform devices including organic electronic devices and displays. Examplesof organic electronic devices that can be made include organictransistors, photovoltaic devices, organic electroluminescent (OEL)devices such as organic light emitting diodes (OLEDs), and the like. Inaddition, these materials and methods can also be useful for non-thermalprinting, patterning, and transfer methods including, for example,inkjet printing, screen printing, and photolithographic patterning.

Organic electroluminescent (OEL) display or device refers toelectroluminescent displays or devices that include an organic emissivematerial, whether that emissive material includes a small molecule (SM)emitter, a SM doped polymer, a light emitting polymer (LEP), a dopedLEP, a blended LEP, or another organic emissive material whetherprovided alone or in combination with any other organic or inorganicmaterials that are functional or non-functional in the OEL display ordevice.

R. H. Friend, et al. (“Electroluminescence in Conjugated Polymers”,Nature, 397, 121 (1999)), incorporated herein by reference, describe onemechanism of electroluminescence as including the “injection ofelectrons from one electrode and holes from the other, the capture ofoppositely charged carriers (so-called recombination), and the radiativedecay of the excited electron-hole state (exciton) produced by thisrecombination process.”

Materials for OEL devices can be small molecule (SM) or polymeric innature. SM materials include charge transporting, charge blocking,semiconducting, and electroluminescent organic and organometalliccompounds. Generally, SM materials can be vacuum deposited or evaporatedto form thin layers in a device. In practice, multiple layers of SMs aretypically used to produce efficient OELs since a given materialgenerally does not have both the desired charge transport andelectroluminescent properties.

LEP materials are typically conjugated polymeric or oligomeric moleculesthat preferably have sufficient film-forming properties for solutionprocessing. Conventionally, LEP materials are utilized by casting asolvent solution of the LEP material on a substrate, and evaporating thesolvent, thereby leaving a polymeric film. Other methods for forming LEPfilms include ink jetting and extrusion coating. Alternatively, LEPs canbe formed in situ on a substrate by reaction of precursor species.Efficient LEP lamps have been constructed with one, two, or more organiclayers.

As an example of device structure, FIG. 1 illustrates an OEL display ordevice 100 that includes a device layer 110 and a substrate 120. Anyother suitable display component can also be included with display 100.Optionally, additional optical elements or other devices suitable foruse with electronic displays, devices, or lamps can be provided betweendisplay 100 and viewer position 140 as indicated by optional element130.

In some embodiments like the one shown, device layer 110 includes one ormore OEL devices that emit light through the substrate toward a viewerposition 140. The viewer position 140 is used generically to indicate anintended destination for the emitted light whether it be an actual humanobserver, a screen, an optical component, an electronic device, or thelike. In other embodiments (not shown), device layer 110 is positionedbetween substrate 120 and the viewer position 140. The deviceconfiguration shown in FIG. 1 (termed “bottom emitting”) may be usedwhen substrate 120 is transmissive to light emitted by device layer 110and when a transparent conductive electrode is disposed in the devicebetween the emissive layer of the device and the substrate. The invertedconfiguration (termed “top emitting”) may be used when substrate 120does or does not transmit the light emitted by the device layer and theelectrode disposed between the substrate and the light emitting layer ofthe device does not transmit the light emitted by the device.

Device layer 110 can include one or more OEL devices arranged in anysuitable manner. For example, in lamp applications (e.g., backlights forliquid crystal display (LCD) modules), device layer 110 might constitutea single OEL device that spans an entire intended backlight area.Alternatively, in other lamp applications, device layer 110 mightconstitute a plurality of closely spaced devices that can becontemporaneously activated. For example, relatively small and closelyspaced red, green, and blue light emitters can be patterned betweencommon electrodes so that device layer 110 appears to emit white lightwhen the emitters are activated. Other arrangements for backlightapplications are also contemplated.

In direct view or other display applications, it may be desirable fordevice layer 110 to include a plurality of independently addressable OELdevices that emit the same or different colors. Each device mightrepresent a separate pixel or a separate sub-pixel of a pixilateddisplay (e.g., high resolution display), a separate segment orsub-segment of a segmented display (e.g., low information contentdisplay), or a separate icon, portion of an icon, or lamp for an icon(e.g., indicator applications).

In at least some instances, an OEL device includes a thin layer, orlayers, of one or more suitable organic materials sandwiched between acathode and an anode. When activated, electrons are injected into theorganic layer(s) from the cathode and holes are injected into theorganic layer(s) from the anode. As the injected charges migrate towardsthe oppositely charged electrodes, they may recombine to formelectron-hole pairs which are typically referred to as excitons. Theregion of the device in which the excitons are generally formed can bereferred to as the recombination zone. These excitons, or excited statespecies, can emit energy in the form of light as they decay back to aground state.

Other layers can also be present in OEL devices such as hole transportlayers, electron transport layers, hole injection layer, electroninjection layers, hole blocking layers, electron blocking layers, bufferlayers, and the like. In addition, photoluminescent materials can bepresent in the electroluminescent or other layers in OEL devices, forexample, to convert the color of light emitted by the electroluminescentmaterial to another color. These and other such layers and materials canbe used to alter or tune the electronic properties and behavior of thelayered OEL device, for example to achieve a desired current/voltageresponse, a desired device efficiency, a desired color, a desiredbrightness, and the like.

FIGS. 4A to 4D illustrate examples of different OEL deviceconfigurations. Each configuration includes a substrate 250, an anode252, a cathode 254, and a light emitting layer 256. The configurationsof FIGS. 4C and 4D also include a hole transport layer 258 and theconfigurations of FIGS. 4B and 4D include an electron transport layer260. These layers conduct holes from the anode or electrons from thecathode, respectively.

The anode 252 and cathode 254 are typically formed using conductingmaterials such as metals, alloys, metallic compounds, metal oxides,conductive ceramics, conductive dispersions, and conductive polymers,including, for example, gold, platinum, palladium, aluminum, calcium,titanium, titanium nitride, indium tin oxide (ITO), fluorine tin oxide(FTO), and polyaniline. The anode 252 and the cathode 254 can be singlelayers of conducting materials or they can include multiple layers. Forexample, an anode or a cathode may include a layer of aluminum and alayer of gold, a layer of calcium and a layer of aluminum, a layer ofaluminum and a layer of lithium fluoride, or a metal layer and aconductive organic layer. As indicated above, in some embodiments one orboth of the electrodes (anode and cathode) is transparent.

The hole transport layer 258 facilitates the injection of holes from theanode into the device and their migration towards the recombinationzone. The hole transport layer 258 can further act as a barrier for thepassage of electrons to the anode 252. The hole transport layer 258 caninclude, for example, a diamine derivative, such asN,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (also known as TPD)or N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1,1′-biphenyl-4,4′-diamine(NPB), or a triarylamine derivative, such as,4,4′,4″-Tris(N,N-diphenylamino)triphenylamine (TDATA) or4,4′,4″-Tris(N-3-methylphenyl-N-phenylamino)triphenylamine (mTDATA).Other examples include copper phthalocyanine (CuPC);1,3,5-Tris(4-diphenylaminophenyl)benzenes (TDAPBs); and other compoundssuch as those described in H. Fujikawa, et al., Synthetic Metals, 91,161 (1997) and J. V. Grazulevicius, P. Strohriegl, “Charge-TransportingPolymers and Molecular Glasses”, Handbook of Advanced Electronic andPhotonic Materials and Devices, H. S. Nalwa (ed.), 10, 233-274 (2001),both of which are incorporated herein by reference.

The electron transport layer 260 facilitates the injection of electronsand their migration towards the recombination zone. The electrontransport layer 260 can further act as a barrier for the passage ofholes to the cathode 254, if desired. As an example, the electrontransport layer 260 can be formed using the organometallic compoundtris(8-hydroxyquinolato) aluminum (Alq3). Other examples of electrontransport materials include1,3-bis[5-(4-(1,1-dimethylethyl)phenyl)-1,3,4-oxadiazol-2-yl]benzene,2-(biphenyl-4-yl)-5-(4-(1,1-dimethylethyl)phenyl)-1,3,4-oxadiazole(tBuPBD) and other compounds described in C. H. Chen, et al., Macromol.Symp. 125, 1 (1997) and J. V. Grazulevicius, P. Strohriegl,“Charge-Transporting Polymers and Molecular Glasses”, Handbook ofAdvanced Electronic and Photonic Materials and Devices, H. S. Nalwa(ed.),10, 233 (2001), both of which are incorporated herein byreference.

The light emitting layer includes a light emitting polymer material andoptionally includes other materials, such as, for example, holetransport material, electron transport material, binder (e.g., apolymeric binder), small molecule emitter material, waveguidingparticles, phosphorescent compounds, and color conversion material.

The light emitting polymer material includes one or more light emittingpolymers. Conventional polymers may be difficult to thermally transferor otherwise deposit on a desired substrate surface. In some instances,it is desirable to select the material on the substrate surface and thematerial to be transferred (e.g., the light emitting polymer material)such that the solubility parameters are compatible. As an example, thematerials can be selected such that the difference in these solubilityparameters is no more than 4 J^(1/2)cm^(−3/2) and, preferably, no morethan 2 J^(1/2)cm^(−3/2) as determined according to “Properties ofPolymers; Their Correlation with Chemical Structure; their NumericalEstimation and Prediction from Additive Group Contributions.” third,completely revised edition by D. W. Van Krevelen; Elsevier SciencePublishers B.V., 1990; Chapter 7, pp 189-225, incorporated herein byreference.

The solubility parameter of a polymer can be determined frommeasurements of the extent of equilibrium swelling of the polymer in arange of solvents of differing solubility parameters. The solubilityparameters of the solvents themselves can be determined from their heatsof evaporation. The solubility parameter δ is related to the cohesiveenergy E_(coh) and the specific volume V by the relationshipδ=(E_(coh)/V)^(1/2). For solvents of low molecular weight, the cohesiveenergy is closely related to the molar heat of evaporation ΔH_(vap)according to E_(coh)=ΔH_(vap)−pΔV=ΔH_(vap)−RT. Thus, E_(coh) and δ canbe calculated from the heat of evaporation of the solvent or from thecourse of the vapor pressure as a function of temperature.

Because polymers cannot be evaporated, indirect methods can be used fordetermination of the solubility parameter. To determine the solubilityparameter of the polymer, one measures the equilibrium swelling of thepolymer in a variety of solvents of differing δ and generates a plot ofequilibrium swelling of the polymer vs. the solubility parameter of thesolvents. The solubility parameter of the polymer is defined as thepoint on this plot where maximum swelling is obtained. Swelling will beless for solvents having solubility parameters that are less than orgreater than that of the polymer. There are also several methods fortheoretically estimating the solubility parameter of a polymer based onthe additive contributions of functional groups present in the polymeras outlined in the above-cited reference.

Some polymers may generate undesirable emission through, for example,excimer formation, as described, for example, in D. Neher, Macromol.Rapid Commun., 22, 1365-1385 (2001), incorporated herein by reference.Light emitting polymers can be selected which reduce excimer andexciplex formation, if desired. For example, the light emitting polymerscan have sterically hindering groups to reduce the formation ofintermolecular or intramolecular configurations that produce excimer orexciplex emission.

Suitable light emitting polymers, according to the invention, includepolymers having arylene monomeric units and soft segment end caps, softsegment side chains, internal soft segments, or combinations thereof, asdescribed below. These polymers can be used alone or in combination witheach other or with other light emitting polymers or small moleculematerials to form the light emitting polymer material. As indicatedbelow, copolymers with more than one arylene monomeric unit can be usedand may be particularly desirable for some embodiments. The softsegments in these light emitting polymers can, if desired, providebetter solubility parameter matching to a receptor substrate than asimilar polymer without the soft segments. In addition or alternatively,the soft segments can alter other properties useful to thermal transferand film stability such as, for example, molecular weight, meltingtemperature, glass transition temperature, percent crystallinity,tendency to crystallize or form aggregates, viscosity, thin filmmorphology, Theological properties such as melt viscosity and relaxationtime, excimer and exciplex formation, cohesive strength, and lightemission frequency, if desired.

The following examples of suitable light emitting polymers utilizemonomer units based on fluorene functional groups. It will be understoodthat other arylene or heteroarylene monomer units can also be used, asdiscussed below. Unless otherwise indicated any of the functional groups(for example, alkyl, aryl, heteroaryl, alkylene, arylene, andheteroarylene functional groups) listed in the following discussion canbe substituted or unsubstituted. In addition, unless otherwiseindicated, for polymers with more than one type of monomer unit thebracketed monomer units of the Formulas illustrated herein can bearranged in any order; for example, the monomer units can be arranged inrandom order, alternating order, or in blocks, to form random,alternating, or block copolymers. In at least some embodiments, thespecific selection of a random copolymer, alternating copolymer, orblock copolymer can be desired.

Examples of light emitting polymers with soft segment end caps areillustrated by Formula 1:

where R₁ and R₁′ are independently hydrogen, C1-C30 alkyl, C6-C20 aryl,C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O,P, or Si atoms; R₂ and R₂′ are independently C1-C20 alkyl, C6-C20 aryl,C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O,P, or Si atoms; a is independently in each occurrence 0 or 1; and n isan integer in the range of 3 to 1000. EC is an end cap group having thegeneral formula*

Ar

_(p)Q—R″where Ar is arylene or heteroarylene, p is 0 or 1, R″ is a stericallyhindering functional group such as an aryl, heteroaryl, or a branchedalkyl, and Q is a soft segment moiety. Preferably, R″ is an aryl, forexample, phenyl or biphenyl. The use of a sterically hinderingfunctional group can reduce or prevent the formation of intermolecularor intramolecular excimer configurations.

In some embodiments, R₁ and R₁′ are independently C1-C30 alkyl, C6-C20aryl, or C3-C20 heteroaryl. In some embodiments, R₁ and R₁′ arepreferably C3-C15 alkyl. In some embodiments, each a is zero.

The soft segment moieties include two or more functional groups selectedfrom ethers, fluoroalkylenes, perfluoroalkylenes, secondary or tertiaryamines, thioethers, esters, dialkylsiloxanes, and dialkoxysiloxanes.These functional groups can be the same or different. Suitable softsegment moieties include, for example, poly(oxyalkylene) functionalities(e.g., —O(C_(q)H_(2q)O)_(s)— or —(C_(q)H_(2q)O)_(s)— where q is aninteger in the range of 1 to 6 and s is an integer in the range of 2 to20) and poly(dimethylsiloxane) or other poly(dialkylsiloxane)functionalities, or a combination thereof. In the solid phase, the softsegment moieties present in the polymer may reside in the same orseparate phase(s) from the remainder of the polymer.

In one embodiment, Ar is phenylene, p is 1, R″ is C6-C20 aryl (forexample, phenyl or biphenyl), and Q is a C2 to C20 poly(oxyalkylene).Examples for making these polymers using Suzuki coupling are illustratedbelow in the Examples.

Copolymers can also be formed. Any comonomer or combination of two ormore comonomers can be used. The incorporation of comonomers into thepolymer may be used to modify the light absorption, light emission,ionization potential, or electron and hole conducting properties of thepolymer that would otherwise be primarily made of 9,9-disubstitutedfluorene groups. Such copolymers can be prepared using methods outlinedin U.S. Pat. No. 6,169,163, incorporated herein by reference. Preferredcomonomers include aryl groups that are conjugated within the comonomer,conjugated (when polymerized) with the fluorene monomers, or both.

Formula 2 illustrates a preferred copolymer.

R₁, R₁′, R₂, R₂′, EC, and a are as described for Formula 1. Ar₁ isselected from C6-C20 arylene, C2-C20 heteroarylene, and C18-C60 divalenttriarylamines. m and n are integers in the range of 2 to 1000. Cappingcan be performed as a separate step, or the monofunctional capping groupcan be added to the growing polymer reaction mixture as a chainterminating reagent.

A variety of methods can be used to make such copolymers. For example,dihalo-functional comonomers are reacted with dihalo-functional fluorenecompounds in nickel coupling polymerization reactions to providerandomly copolymerized polymers that are terminated with reactive halidegroups. Reaction with monofunctional capping groups EC give rise torandomly copolymerized and soft segment end capped structures.

In another method using Suzuki coupling, one or more dibromo functionalcomonomers can be used in conjunction with fluorene-diboronic acid orfluorene-diboronates to prepare alternating copolymers bearing reactiveend groups. Likewise, conjugated comonomers bearing diboronic acid ordiboronate functionalities can be used in conjunction with2,7-dibromofluorenes to give rise to alternating copolymers bearingreactive end groups.

Furthermore, by reaction of difunctional comonomers with mixtures ofdifferent 2,7-dibromofluorenes or 2,7-diboronyl fluorenes one canprepare copolymers having varying mole fractions of the comonomers,polymerized in an alternating fashion with the fluorene monomers.Subsequent reaction of any of these polymers with monofunctional cappinggroups EC can give rise to alternating copolymers and terpolymersbearing soft segment end capping groups. For example, polymers such asthose illustrated in Formulas 3 and 4 can be formed.

R₁, R₁′, R₂, R₂′, EC and a are as described for Formula 1. R₃, R₃′, R₄,R₄′ are independently hydrogen, C1-C30 alkyl, C6-C20 aryl, C3-C20heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O, P, orSi atoms. In some embodiments, R₃ and R₃′ are independently C1-C30alkyl, C6-C20 aryl, or C3-C20 heteroaryl. In some embodiments, R₃ andR₃′ are preferably C3 to C15 alkyl.

Ar₁ and Ar₂ are independently selected from C6-C20 arylene, C2-C20heteroarylene, and C18-C60 divalent triarylamines. m and n are integersin the range of 2 to 1000. It will be understood that polymers withadditional comonomers can be formed using the techniques describedabove.

Examples of light emitting polymers with soft segment side chains areillustrated in Formula 5:

where R₁ and R₁′ are independently hydrogen, C1-C30 alkyl, C6-C20 aryl,C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O,P, or Si atoms; R₂, R₂′, R₄, and R₄′ are independently C1-C20 alkyl,C6-C20 aryl, C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one ormore S, N, O, P, or Si atoms; a is independently in each occurrence 0 or1; and m and n are nonzero integers whose sum (m+n) is in the range of 3to 1000 and where the ratio n/m is in the range of 0.1 to 3.

X and Y can be any capping group used for polymers including, forexample, aryl, heteroaryl, triarylamine, or soft segment end cap groups(EC) as described above with respect to Formula 1. In some embodiments,the polymer is a reactive intermediate to a further polymer. In theseinstances, one or both of the capping groups can be a reactive groupsuch as a boralane, halo (for example, bromine), or hydroxy group.

In some embodiments, R₁ and R₁′ are independently C1-C30 alkyl, C6-C20aryl, or C3-C20 heteroaryl. In some embodiments, R₁ and R₁′ arepreferably C3 to C15 alkyl. In some embodiments, each a is zero.

Z₁, and Z₂ are independently soft segment side chains having the generalformula*

Ar

_(p)Q—R″where Ar is arylene or heteroarylene, p is 0 or 1, R″ is alkyl, aryl, orheteroaryl, Q is a soft segment moiety. The soft segment moietiesinclude two or more functional groups selected from ethers,fluoroalkylenes, perfluoroalkylenes, secondary or tertiary amines,thioethers, esters, dialkylsiloxanes, and dialkoxysiloxanes. Thesefunctional groups can be the same or different. Suitable soft segmentmoieties include, for example, poly(oxyalkylene) groups (e.g.,—O(C_(q)H_(2q)O)_(s)— or —(C_(q)H_(2q)O)_(s)— where q is an integer inthe range of 1 to 6 and s is an integer in the range of 2 to 20) andpoly(dimethylsiloxane) or other poly(dialkylsiloxane) functionalities.

In some embodiments, Z₁, and Z₂ are the same. In some embodiments, R″ isa sterically hindering functional group such as an aryl, heteroaryl, ora branched alkyl. In other embodiments, R″ is an alkyl, such as methyl,ethyl, or propyl. In some instances, such a functional group may preventor reduce excimer formation. Preferably, p is 0 and Q is a C2 to C20poly(oxyalkylene). In some embodiments, the ratio n/m can be used tofine tune the color (including fine tuning the color for white lightemission applications), adjust the solubility parameter of the polymerfor better thermal transfer, reduce crystallization effects that degradelifetime, improve or control morphology of thin films or film made byblending the polymer with other agents, or provide any combination ofthese advantages.

Polymers of Formula 5 can be prepared as random copolymers using thenickel coupling chemistries described above, and capped withmonofunctional aryls or soft segment capping groups. In this case, theratio n/m can be varied by the relative amounts of the twodihalo-functional fluorene monomers used in the reaction. Alternatingcopolymers can be made using Suzuki coupling methods.

Random copolymers with additional difunctional arylene comonomers Ar₁can be prepared by nickel coupling to give polymers according to Formula6:

R₁, R₁′, R₂, R₂′, R₄, R₄′, Z₁, Z₂, X, Y and a are as described forFormula 5. Ar₁ is selected from C6-C20 arylene, C2-C20 heteroarylene,and C18-C60 divalent triarylamines. 1, m and n are integers in the rangeof 2 to 1000.

Alternating copolymers and terpolymers with varying mole ratios of oneor more reactive conjugated comonomers can be obtained using Suzukicoupling methods as described above. For example, polymers such as thoseillustrated in Formulas 7, 8, and 9 can be formed.

R₁, R₁′, R₂, R₂′, R₄, R₄′, Z₁, Z₂, X, Y, and a are as described forFormula 5. Ar₁ and Ar₂ are independently selected from C6-C20 arylene,C2-C20 heteroarylene, and C18-C60 divalent triarylamines. m and n areintegers in the range of 2 to 1000. It will be understood that polymerscontaining monomer units with soft segment side chains can be formedwith one, two, three, four, or more comonomers using the techniquesdescribed above.

Examples of light emitting polymers with internal soft segments areillustrated in Formulas 10 and 11:

where R₁ and R₁′ are independently hydrogen, C1-C30 alkyl, C6-C20 aryl,C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O,P, or Si atoms (including soft segment-containing moieties as describedabove for substituents Z₁, and Z₂ in Formula 5), R₂ and R₂′ areindependently C1-C20 alkyl, C6-C20 aryl, C3-C20 heteroaryl, or C1-C30hydrocarbyl containing one or more S, N, O, P, or Si atoms; a isindependently in each occurrence 0 or 1; n is an integer in the range of2 to 600 (preferably in the range of 6 to 200 or 6 to 30), and m is aninteger in the range of 2 to 100. X and Y are capping groups asdescribed above with respect to Formula 5. In some embodiments, X and Yare preferably aryl or soft segment end cap groups (EC) as describedabove with respect to Formula 1.

In some embodiments, R₁ and R₁′ are independently C1-C30 alkyl, C6-C20aryl, or C3-C20 heteroaryl. In some embodiments, R₁ and R₁′ arepreferably C3 to C15 alkyl. In some embodiments, each a is zero.

T is an internal soft segment moiety. The soft segment moieties includetwo or more functional groups selected from alkylenes, ethers,fluoroalkylenes, perfluoroalkylenes, secondary or tertiary amines,thioethers, esters, dialkylsiloxanes, and dialkoxysiloxanes. Thesefunctional groups can be the same or different. Suitable soft segmentmoieties include, for example, oxyalkylene (e.g., —OC_(q)H_(2q)O— whereq is an integer in the range of 1 to 10), poly(oxyalkylene) groups(e.g., —O(C_(q)H_(2q)O)_(s)— or —(C_(q)H_(2q)O)_(s)— where q is aninteger in the range of 1 to 6 and s is an integer in the range of 2 to20), and poly(dialkylsiloxanes). Preferably, T is a C2 to C20poly(oxyalkylene). Other examples of particularly suitable soft segmentmoieties, T, include —(Ar₃)_(w)-G-(Ar₄)_(v)— where w and v are 0 or 1,Ar₃ and Ar₄ are independently selected from C6-C20 arylene and C2-C20heteroarylene and G includes two or more of the soft segment moietiesdescribed above. For example, w and v can be 1, Ar₃ and Ar₄ can bephenyl or biphenyl, and G can be a poly(oxyalkylene).

Polymers of Formulas 10 and 11 can be prepared, for example, bysynthesizing a difunctional reactive oligomer of the desiredelectroluminescent polymer (for example, a polyfluorene), and thenreacting this with a difunctional reactive monomer representing the softsegment. The reactive oligomer of the electroluminescent polymer can beprepared using the nickel coupling chemistries described above or theSuzuki coupling chemistries described above. Reaction of a dihalideterminated oligomer of the electroluminescent polymer can be reactedwith a dihalide terminated soft segment monomer using nickel couplingchemistry. Alternatively, the dibromo terminated oligomer of theelectroluminescent polymer can be converted to the correspondingdiboralane and then polymerized with the dibromine terminated softsegment monomer using Suzuki coupling chemistry. The resulting polymeris an alternating block copolymer and can then be capped withmonofunctional arylenes or soft segment capping groups EC. In this case,the ratio of soft-segment and electroluminescent oligomer in theresulting polymer is determined by the molecular weight of thecorresponding block oligomers.

Random copolymers with additional difunctional arylene comonomers Ar₁can be prepared by nickel coupling to give polymers according toFormulas 12 and 13:

R₁, R₁′, R₂, R₂′, X, Y, T, and a are as described for Formula 10. Ar₁ isselected from C6-C20 arylene, C2-C20 heteroarylene, and C18-C60 divalenttriarylamines. k, l, m and n are integers in the range of 2 to 1000.

Alternating, block, and random copolymers (including terpolymers) withvarying molar ratios of one or more reactive conjugated comonomers canbe obtained using Suzuki coupling methods as described above. Forexample, polymers such as those illustrated in Formulas 14, 15, 16, and17 can be formed.

R₁, R₁′, R₂, R₂′, X, Y, T, and a are as described for Formula 10. R₃,R₃′, R₄, R₄′ are independently hydrogen, C1-C30 alkyl, C6-C20 aryl,C3-C20 heteroaryl, or C1-C30 hydrocarbyl containing one or more S, N, O,P, or Si atoms. In some embodiments, R₃ and R₃′ are independently C1-C30alkyl, C6-C20 aryl, or C3-C20 heteroaryl. In some embodiments, R₃ andR₃′ are preferably C3 to C15 alkyl.

Ar₁ and Ar₂ are independently selected from C6-C20 arylene, C2-C20heteroarylene, and C18-C60 divalent triarylamines. l, m, n, and o areintegers in the range of 2 to 1000. In alternative embodiments, eitherAr₁ or Ar₂ is omitted from Formulas 14 or 15. It will be understood thatpolymers containing monomer units and internal soft segments can beformed with one, two, three, four, or more comonomers using thetechniques described above.

Other light emitting polymers with soft segment end caps, soft segmentsidechains, internal soft segments, or combinations thereof can beformed using core arylene (D₁ and D₂) moieties other than fluorene-typemoieties. In other words, in any of Formulas 1-17, one or more of thefluorene moieties can be replaced with another phenylene-type ornaphthalene-type moiety, described below, as illustrated in Formulas1′-17′.

EC, T, X, Y, Ar₁, Ar₂, Z₁, l, m, n, o, and q are as described above forthe respective Formulas 1-17.

D₁ and D₂ are arylene moieties, such as phenylene-type moieties andnaphthalene-type moieties. Phenylene-type moieties include any divalentunsaturated aromatic carbocyclic units having one, two, or threeconjugated phenylene rings (for example, phenylene, biphenylene, andtriphenylene) where, optionally, two or more of the phenylene rings arefused together with a divalent alkylene, dialkylsilylene, ordiarylsilylene moiety. Examples of such groups include benzene-1,3-diyl,benzene-1,4-diyl, 5,6-dihydrophenathren-3,8-diyl,4,5,9,10-tetrahydropyren-2,7-diyl, fluoren-2,7-diyl,9-silafluoren-2,7-diyl, spirobisfluoren-2,7-diyl,6,12-dihydroindeno[1,2-b]fluorene-2,8-diyl,5,6,12,13-tetrahydrodibenzo[a,h]anthracene-3,10-diyl,5,12-dihydro-6H-indeno[1,2-b]phenathrene-3,10-diyl, and the like.Structural examples of phenylene-type moieties include, for example:

where R⁵ is independently in each case hydrogen, C1-C30 alkyl, C1-C30alkenyl, C6-C20 aryl, C3-C20 heteroaryl, or C1-C30 hydrocarbylcontaining one or more S, N, O, P, or Si atoms and where any of thearomatic or aliphatic rings can be independently substituted one or moretimes with fluoro, C1-C20 fluoroalkyl, C1-C20 perfluoroalkyl, C1-C20alkyl, C1-C20 alkenyl, C6-C20 aryl, C3-C20 heteroaryl, or C1-C30hydrocarbyl containing one or more S, N, O, P, or Si atoms.

Naphthalene-type moieties include any divalent unsaturated aromaticcarbocyclic radicals having a fused naphthalene ring structure. Examplesof preferred “naphthalene-type moieties” as used herein includenaphthalene-2,7-diyl, naphthalene-2,6-diyl, naphthalene-1,4-diyl, andnaphthalene-1,5-diyl. Structural examples of naphthalene-type moietiesinclude, for example:

Any of the aromatic rings can be independently substituted one or moretimes with fluoro, C1-C20 fluoroalkyl, C1-C20 perfluoroalkyl, C1-C20alkyl, C1-C20 alkenyl, C6-C20 aryl, C3-C20 heteroaryl, or C1-C30hydrocarbyl containing one or more S, N, O, P, or Si atoms.

It will be understood that polymers containing the above-described corearylene moieties, soft segment end caps, soft segment side chains, andinternal soft segments can be formed with one, two, three, four, or morecomonomers using the techniques described above.

Unless otherwise indicated, the term “alkyl” includes bothstraight-chained, branched, and cyclic alkyl groups and includes bothunsubstituted and substituted alkyl groups. Unless otherwise indicated,the alkyl groups are typically C1-C20. Examples of “alkyl” as usedherein include, but are not limited to, methyl, ethyl, n-propyl,n-butyl, n-pentyl, isobutyl, and isopropyl, and the like.

Unless otherwise indicated, the term “alkylene” includes bothstraight-chained, branched, and cyclic divalent hydrocarbon radicals andincludes both unsubstituted and substituted alkenylene groups. Unlessotherwise indicated, the alkylene groups are typically C1-C20. Examplesof “alkylene” as used herein include, but are not limited to, methylene,ethylene, propylene, butylene, and isopropylene, and the like.

Unless otherwise indicated, the term “aryl” refers to monovalentunsaturated aromatic carbocyclic radicals having one to fifteen rings,such as phenyl or biphenyl, or multiple fused rings, such as naphthyl oranthryl, or combinations thereof. Examples of aryl as used hereininclude, but are not limited to, phenyl, 2-naphthyl, 1-naphthyl,acenaphthyl, phenanthryl, anthracenyl, fluoranthenyl, pyrenyl, rubrenyl,chrysenyl, biphenyl, 2-hydroxyphenyl, 2-aminophenyl, 2-methoxyphenyl andthe like.

Unless otherwise indicated, the term “arylene” refers to divalentunsaturated aromatic carbocyclic radicals having one to fifteen rings,such as phenylene, or multiple fused rings, such as naphthylene oranthrylene, or combinations thereof. Examples of “arylene” as usedherein include, but are not limited to, benzene-1,2-diyl,benzene-1,3-diyl, benzene-1,4-diyl, naphthalene-1,8-diyl,anthracene-1,4-diyl, and the like.

Unless otherwise indicated, the term “heteroaryl” refers to functionalgroups containing a monovalent five—to seven—membered aromatic ringradical with one or more heteroatoms independently selected from S, O,or N. Such a heteroaryl ring may be optionally fused to one or more ofanother heterocyclic ring(s), heteroaryl ring(s), aryl ring(s),cycloalkenyl ring(s), or cycloalkyl rings. Examples of “heteroaryl” usedherein include, but are not limited to, furyl, thiophenyl, pyrrolyl,imidazolyl, pyrazolyl, triazolyl, tetrazolyl, thiazolyl, oxazolyl,isoxazolyl, oxadiazolyl, thiadiazolyl, isothiazolyl, pyridinyl,pyridazinyl, pyrazinyl, pyrimidinyl, quinolinyl, isoquinolinyl,benzofuryl, benzothiophenyl, indolyl, carbazoyl, benzoxazolyl,benzothiazolyl, benzimidazolyl, cinnolinyl, quinazolinyl, quinoxalinyl,phthalazinyl, benzothiadiazolyl, benzotriazinyl, phenazinyl,phenanthridinyl, acridinyl, and indazolyl, and the like.

Unless otherwise indicated, the term “heteroarylene” refers tofunctional groups containing a divalent five to seven membered aromaticring radical with one or more heteroatoms independently selected from S,O, or N. Such a heteroarylene ring may be optionally fused to one ormore of another heterocyclic ring(s), heteroaryl ring(s), aryl ring(s),cycloalkenyl ring(s), or cycloalkyl rings. Examples of “heteroarylene”used herein include, but are not limited to, furan-2,5-diyl,thiophene-2,4-diyl, 1,3,4-oxadiazole-2,5-diyl,1,3,4-thiadiazole-2,5-diyl, 1,3-thiazole-2,4-diyl,1,3-thiazole-2,5-diyl, pyridine-2,4-diyl, pyridine-2,3-diyl,pyridine-2,5-diyl, pyrimidine-2,4-diyl, quinoline-2,3-diyl, and thelike.

Unless otherwise indicated, the term “triarylamine” refers to a class ofdivalent or monovalent functional groups comprising one or more tertiarynitrogen centers, each bonded to three aryl or arylene groups. Examplesof suitable “triarylamines” used herein include the monovalent ordivalent forms of diarylanilines, alkylcarbazoles, arylcarbazoles,tetraaryldiamines such as N,N,N′N′-tetraarylbenzidines,N,N,N′,N′-tetraaryl- 1,4-phenylenediamines, N,N,N′N′-tetraryl-2,7-diaminofluorene derivatives such as those taught inEuropean Patent Application Publication No. 0 953 624 and EuropeanPatent Application Publication No. 0 879 868 (both incorporated hereinby reference), N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine (alsoknown as TPD),N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1,1′-biphenyl-4,4′-diamine(also known as NPB), N,N′-dicarbazole-biphenyl (also known as CBP),other tetraaryldiamine derivatives such as those described in Koene etal., Chem. Mater. 10, 2235-2250 (1998), incorporated herein byreference, and in U.S. Pat. Nos. 5,792,557 and 5,550,290, and EuropeanPatent Application Publication No. 0891121, all of which areincorporated herein by reference; peraryltriamine derivatives such asthose described in U.S. Pat. No. 6,074,734 and EP 0827367, both of whichare incorporated herein by reference, starburst amine derivatives suchas 4,4′,4″-tris(N,N-diarylamino)triphenylamines and1,3,5-tris(4-(N,N-diarylamino)phenyl)benzenes,4,4′,4′-tris(N,N-diphenylamino)triphenylamine (also known as TDATA),1,3,5-tris(4-(N,N-diphenylamino)phenyl)benzenes (TDAPBs), and otherdendridic and spiro amine derivatives as taught in European PatentApplication Publication No. 0650955; Tokito et al., Polym. Prep. (Am.Chem. Soc. Div. Polym. Chem.) 38(1), 388-389, (1997); Tanake et al.,Chem. Commun. 2175-2176 (1996); and Tokito et al., Appl. Phys. Lett.70(15), 1929-1931 (1997), all of which are incorporated herein byreference.

Unless otherwise indicated, all alkyl, alkylene, aryl, arylene,heteroaryl, heteroarylene, and triarylamine groups can be unsubstitutedor substituted with one or more substituents. Suitable substituents forsubstituted alkyl, alkylene, aryl, arylene, heteroaryl, heteroarylene,and triarylamine groups include, but are not limited to, alkyl,alkylene, alkoxy, aryl, arylene, heteroaryl, heteroarylene, aryloxy,thioalkyl, thioaryl, amino, F, Cl, cyano, nitro, and —COO-alkyl.

Light emitting layers based on LEP materials have been fabricated bysolution coating a thin layer of the material as described, for example,in U.S. Pat. No. 5,408,109, incorporated herein by reference.

Another method of forming devices includes the transfer of one or moretransfer layers by laser thermal patterning as described in, forexample, U.S. Pat. Nos. 6,358,664; 6,284,425; 6,242,152; 6,228,555;6,228,543; 6,221,553; 6,221,543; 6,214,520; 6,194,119; 6,114,088;5,998,085; 5,725,989; 5,710,097; 5,695,907; and 5,693,446, and in U.S.patent application Ser. Nos. 09/844,695; 09/844,100; 09/662,980;09/451,984; 09/931,598; and 10/004,706, all of which are incorporatedherein by reference. The patterning process can depend upon the physicalproperties of the transfer layer.

One parameter is the cohesive, or film strength, of the transfer layer.During imaging, the transfer layer preferably breaks cleanly along theline dividing imaged and unimaged regions to form the edge of a pattern.Highly conjugated polymers which exist in extended chain conformations,such as polyphenylenevinylenes, can have high tensile strengths andelastic moduli comparable to that of polyaramide fibers. In practice,clean edge formation during the laser thermal imaging of light emittingpolymers can be challenging. The undesired consequence of poor edgeformation is rough, torn, or ragged edges on the transferred pattern.Another parameter is the strength of the bond formed between thetransfer layer and the receptor surface. This strength may be influencedby the solubility parameter compatibility of the transfer layer and thereceptor surface.

Laser thermal transfer will be used as an example of a method forforming light emitting and other layers, however, it will be recognizedthat other transfer, patterning, and printing techniques can be used,such as inkjet printing, screen printing, thermal head printing, andphotolithographic patterning.

Referring back to FIG. 1, device layer 110 is disposed on substrate 120.Substrate 120 can be any substrate suitable for OEL device and displayapplications. For example, substrate 120 can comprise glass, clearplastic, or other suitable material(s) that are substantiallytransparent to visible light. Substrate 120 can also be opaque tovisible light, for example stainless steel, crystalline silicon,polysilicon, or the like. Because some materials in OEL devices can beparticularly susceptible to damage due to exposure to oxygen or water,substrate 120 preferably provides an adequate environmental barrier, oris supplied with one or more layers, coatings, or laminates that providean adequate environmental barrier.

Substrate 120 can also include any number of devices or componentssuitable in OEL devices and displays such as transistor arrays and otherelectronic devices; color filters, polarizers, wave plates, diffusers,and other optical devices; insulators, barrier ribs, black matrix, maskwork and other such components; and the like. Generally, one or moreelectrodes will be coated, deposited, patterned, or otherwise disposedon substrate 120 before forming the remaining layer or layers of the OELdevice or devices of the device layer 110. When a light transmissivesubstrate 120 is used and the OEL device or devices are bottom emitting,the electrode or electrodes that are disposed between the substrate 120and the emissive material(s) are preferably substantially transparent tolight, for example transparent conductive electrodes such as indium tinoxide (ITO) or any of a number of other transparent conductive oxides.

Element 130 can be any element or combination of elements suitable foruse with OEL display or device 100. For example, element 130 can be anLCD module when device 100 is a backlight. One or more polarizers orother elements can be provided between the LCD module and the backlightdevice 100, for instance an absorbing or reflective clean-up polarizer.Alternatively, when device 100 is itself an information display, element130 can include one or more of polarizers, wave plates, touch panels,antireflective coatings, anti-smudge coatings, projection screens,brightness enhancement films, or other optical components, coatings,user interface devices, or the like.

Organic electronic devices containing materials for light emission canbe made at least in part by selective thermal transfer of light emittingmaterial from a thermal transfer donor sheet to a desired receptorsubstrate. For example, light emitting polymer displays and lamps can bemade coating an LEP on a donor sheet and then selectively transferringthe LEP layer alone or along with other device layers or materials tothe display substrate.

Selective thermal transfer of layers containing light emitting materialsfor organic electronic devices can be performed using a thermal transferdonor. FIG. 2 shows an example of a thermal transfer donor 200 suitablefor use in the present invention. Donor element 200 includes a basesubstrate 210, an optional underlayer 212, an optional light-to-heatconversion layer (LTHC layer) 214, an optional interlayer 216, and atransfer layer 218. Each of these elements are described in more detailin the discussion that follows. Other layers can also be present.Examples of suitable donors or layers of donors are disclosed in U.S.Pat. Nos. 6,358,664; 6,284,425; 6,242,152; 6,228,555; 6,228,543;6,221,553; 6,221,543; 6,214,520; 6,194,119; 6,114,088; 5,998,085;5,725,989; 5,710,097; 5,695,907; and 5,693,446, and in U.S. patentapplications Ser. Nos. 09/844,695; 09/844,100; 09/662,980; 09/451,984;09/931,598; and 10/004,706, all of which are incorporated herein byreference.

In processes of the present invention, emissive organic materials,including LEPs or other materials, can be selectively transferred fromthe transfer layer of a donor sheet to a receptor substrate by placingthe transfer layer of the donor element adjacent to the receptor andselectively heating the donor element. Illustratively, the donor elementcan be selectively heated by irradiating the donor element with imagingradiation that can be absorbed by light-to-heat converter materialdisposed in the donor, often in a separate LTHC layer, and convertedinto heat. In these cases, the donor can be exposed to imaging radiationthrough the donor substrate, through the receptor, or both. Theradiation can include one or more wavelengths, including visible light,infrared radiation, or ultraviolet radiation, for example from a laser,lamp, or other such radiation source. Other selective heating methodscan also be used, such as using a thermal print head or using a thermalhot stamp (e.g., a patterned thermal hot stamp such as a heated siliconestamp that has a relief pattern that can be used to selectively heat adonor). Material from the thermal transfer layer can be selectivelytransferred to a receptor in this manner to imagewise form patterns ofthe transferred material on the receptor. In many instances, thermaltransfer using light from, for example, a lamp or laser, to patternwiseexpose the donor can be advantageous because of the accuracy andprecision that can often be achieved. The size and shape of thetransferred pattern (e.g., a line, circle, square, or other shape) canbe controlled by, for example, selecting the size of the light beam, theexposure pattern of the light beam, the duration of directed beamcontact with the donor sheet, or the materials of the donor sheet. Thetransferred pattern can also be controlled by irradiating the donorelement through a mask.

As mentioned, a thermal print head or other heating element (patternedor otherwise) can also be used to selectively heat the donor elementdirectly, thereby patternwise transferring portions of the transferlayer. In such cases, the light-to-heat converter material in the donorsheet is optional. Thermal print heads or other heating elements may beparticularly suited for making lower resolution patterns of material orfor patterning elements whose placement need not be preciselycontrolled.

Transfer layers can also be transferred from donor sheets withoutselectively transferring the transfer layer. For example, a transferlayer can be formed on a donor substrate that, in essence, acts as atemporary liner that can be released after the transfer layer iscontacted to a receptor substrate, typically with the application ofheat or pressure. Such a method, referred to as lamination transfer, canbe used to transfer the entire transfer layer, or a large portionthereof, to the receptor.

The mode of thermal mass transfer can vary depending on the type ofselective heating employed, the type of irradiation if used to exposethe donor, the type of materials and properties of the optional LTHClayer, the type of materials in the transfer layer, the overallconstruction of the donor, the type of receptor substrate, and the like.Without wishing to be bound by any theory, transfer generally occurs viaone or more mechanisms, one or more of which may be emphasized orde-emphasized during selective transfer depending on imaging conditions,donor constructions, and so forth. One mechanism of thermal transferincludes thermal melt-stick transfer whereby localized heating at theinterface between the thermal transfer layer and the rest of the donorelement can lower the adhesion of the thermal transfer layer to thedonor in selected locations. Selected portions of the thermal transferlayer can adhere to the receptor more strongly than to the donor so thatwhen the donor element is removed, the selected portions of the transferlayer remain on the receptor. Another mechanism of thermal transferincludes ablative transfer whereby localized heating can be used toablate portions of the transfer layer off of the donor element, therebydirecting ablated material toward the receptor. Yet another mechanism ofthermal transfer includes sublimation whereby material dispersed in thetransfer layer can be sublimated by heat generated in the donor element.A portion of the sublimated material can condense on the receptor. Thepresent invention contemplates transfer modes that include one or moreof these and other mechanisms whereby selective heating of a donor sheetcan be used to cause the transfer of materials from a transfer layer toreceptor surface.

A variety of radiation-emitting sources can be used to heat donorsheets. For analog techniques (e.g., exposure through a mask),high-powered light sources (e.g., xenon flash lamps and lasers) areuseful. For digital imaging techniques, infrared, visible, andultraviolet lasers are particularly useful. Suitable lasers include, forexample, high power (≧100 mW) single mode laser diodes, fiber-coupledlaser diodes, and diode-pumped solid state lasers (e.g., Nd:YAG andNd:YLF). Laser exposure dwell times can vary widely from, for example, afew hundredths of microseconds to tens of microseconds or more, andlaser fluences can be in the range from, for example, about 0.0 1 toabout 5 J/cm² or more. Other radiation sources and irradiationconditions can be suitable based on, among other things, the donorelement construction, the transfer layer material, the mode of thermalmass transfer, and other such factors.

When high spot placement accuracy is desired (e.g., when patterningelements for high information content displays and other suchapplications) over large substrate areas, a laser can be particularlyuseful as the radiation source. Laser sources are also compatible withboth large rigid substrates (e.g., 1 m×1 m ×1.1 mm glass) and continuousor sheeted film substrates (e.g., 100 μm thick polyimide sheets).

During imaging, the donor sheet can be brought into intimate contactwith a receptor (as might typically be the case for thermal melt-sticktransfer mechanisms) or the donor sheet can be spaced some distance fromthe receptor (as can be the case for ablative transfer mechanisms ormaterial sublimation transfer mechanisms). In at least some instances,pressure or vacuum can be used to hold the donor sheet in intimatecontact with the receptor. In some instances, a mask can be placedbetween the donor sheet and the receptor. Such a mask can be removableor can remain on the receptor after transfer. If a light-to-heatconverter material is present in the donor, radiation source can then beused to heat the LTHC layer (or other layer(s) containing radiationabsorber) in an imagewise fashion (e.g., digitally or by analog exposurethrough a mask) to perform imagewise transfer or patterning of thetransfer layer from the donor sheet to the receptor.

Typically, selected portions of the transfer layer are transferred tothe receptor without transferring significant portions of the otherlayers of the donor sheet, such as the optional interlayer or LTHClayer. The presence of the optional interlayer may eliminate or reducethe transfer of material from an LTHC layer to the receptor or reducedistortion in the transferred portion of the transfer layer. Preferably,under imaging conditions, the adhesion of the optional interlayer to theLTHC layer is greater than the adhesion of the interlayer to thetransfer layer. The interlayer can be transmissive, reflective, orabsorptive to imaging radiation, and can be used to attenuate orotherwise control the level of imaging radiation transmitted through thedonor or to manage temperatures in the donor, for example to reducethermal or radiation-based damage to the transfer layer during imaging.Multiple interlayers can be present.

Large donor sheets can be used, including donor sheets that have lengthand width dimensions of a meter or more. In operation, a laser can berastered or otherwise moved across the large donor sheet, the laserbeing selectively operated to illuminate portions of the donor sheetaccording to a desired pattern. Alternatively, the laser may bestationary and the donor sheet or receptor substrate moved beneath thelaser.

In some instances, it may be necessary, desirable, or convenient tosequentially use two or more different donor sheets to form electronicdevices on a receptor. For example, multiple layer devices can be formedby transferring separate layers or separate stacks of layers fromdifferent donor sheets. Multilayer stacks can also be transferred as asingle transfer unit from a single donor element. For example, a holetransport layer and a LEP layer can be co-transferred from a singledonor. As another example, a semiconductive polymer and an emissivelayer can be co-transferred from a single donor. Multiple donor sheetscan also be used to form separate components in the same layer on thereceptor. For example, three different donors that each have a transferlayer comprising a LEP capable of emitting a different color (forexample, red, green, and blue) can be used to form RGB sub-pixel OELdevices for a full color polarized light emitting electronic display. Asanother example, a conductive or semiconductive polymer can be patternedvia thermal transfer from one donor, followed by selective thermaltransfer of emissive layers from one or more other donors to form aplurality of OEL devices in a display. As still another example, layersfor organic transistors can be patterned by selective thermal transferof electrically active organic materials (oriented or not), followed byselective thermal transfer patterning of one or more pixel or sub-pixelelements such as color filters, emissive layers, charge transportlayers, electrode layers, and the like.

Materials from separate donor sheets can be transferred adjacent toother materials on a receptor to form adjacent devices, portions ofadjacent devices, or different portions of the same device.Alternatively, materials from separate donor sheets can be transferreddirectly on top of, or in partial overlying registration with, otherlayers or materials previously patterned onto the receptor by thermaltransfer or some other method (e.g., photolithography, depositionthrough a shadow mask, etc.). A variety of other combinations of two ormore donor sheets can be used to form a device, each donor sheet formingone or more portions of the device. It will be understood that otherportions of these devices, or other devices on the receptor, may beformed in whole or in part by any suitable process includingphotolithographic processes, ink jet processes, and various otherprinting or mask-based processes, whether conventionally used or newlydeveloped.

Referring back to FIG. 2, various layers of the donor sheet 200 will nowbe described.

The donor substrate 210 can be a polymer film. One suitable type ofpolymer film is a polyester film, for example, polyethyleneterephthalate (PET) or polyethylene naphthalate (PEN) films. However,other films with sufficient optical properties, including hightransmission of light at a particular wavelength, or sufficientmechanical and thermal stability properties, depending on the particularapplication, can be used. The donor substrate, in at least someinstances, is flat so that uniform coatings can be formed thereon. Thedonor substrate is also typically selected from materials that remainstable despite heating of one or more layers of the donor. However, asdescribed below, the inclusion of an underlayer between the substrateand an LTHC layer can be used to insulate the substrate from heatgenerated in the LTHC layer during imaging. The typical thickness of thedonor substrate ranges from 0.025 to 0.15 mm, preferably 0.05 to 0.1 mm,although thicker or thinner donor substrates may be used.

The materials used to form the donor substrate and an optional adjacentunderlayer can be selected to improve adhesion between the donorsubstrate and the underlayer, to control heat transport between thesubstrate and the underlayer, to control imaging radiation transport tothe LTHC layer, to reduce imaging defects and the like. An optionalpriming layer can be used to increase uniformity during the coating ofsubsequent layers onto the substrate and also increase the bondingstrength between the donor substrate and adjacent layers.

An optional underlayer 212 may be coated or otherwise disposed between adonor substrate and the LTHC layer, for example to control heat flowbetween the substrate and the LTHC layer during imaging or to providemechanical stability to the donor element for storage, handling, donorprocessing, or imaging. Examples of suitable underlayers and methods ofproviding underlayers are disclosed in U.S. Pat. No. 6,284,425,incorporated herein by reference.

The underlayer can include materials that impart desired mechanical orthermal properties to the donor element. For example, the underlayer caninclude materials that exhibit a low value for the product of specificheat and density or low thermal conductivity relative to the donorsubstrate. Such an underlayer may be used to increase heat flow to thetransfer layer, for example to improve the imaging sensitivity of thedonor.

The underlayer may also include materials for their mechanicalproperties or for adhesion between the substrate and the LTHC. Using anunderlayer that improves adhesion between the substrate and the LTHClayer may result in less distortion in the transferred image. As anexample, in some cases an underlayer can be used that reduces oreliminates delamination or separation of the LTHC layer, for example,that might otherwise occur during imaging of the donor media. This canreduce the amount of physical distortion exhibited by transferredportions of the transfer layer. In other cases, however it may bedesirable to employ underlayers that promote at least some degree ofseparation between or among layers during imaging, for example toproduce an air gap between layers during imaging that can provide athermal insulating function. Separation during imaging may also providea channel for the release of gases that may be generated by heating ofthe LTHC layer during imaging. Providing such a channel may lead tofewer imaging defects.

The underlayer may be substantially transparent at the imagingwavelength, or may also be at least partially absorptive or reflectiveof imaging radiation. Attenuation or reflection of imaging radiation bythe underlayer may be used to control heat generation during imaging.

Referring again to FIG. 2, an LTHC layer 214 can be included in donorsheets of the present invention to couple irradiation energy into thedonor sheet. The LTHC layer preferably includes a radiation absorberthat absorbs incident radiation (e.g., laser light) and converts atleast a portion of the incident radiation into heat to enable transferof the transfer layer from the donor sheet to the receptor.

Generally, the radiation absorber(s) in the LTHC layer absorb light inthe infrared, visible, or ultraviolet regions of the electromagneticspectrum and convert the absorbed radiation into heat. The radiationabsorber(s) are typically highly absorptive of the selected imagingradiation, providing a LTHC layer with an optical density at thewavelength of the imaging radiation in the range of about 0.2 to 3 orhigher. Optical density of a layer is the absolute value of thelogarithm (base 10) of the ratio of the intensity of light transmittedthrough the layer to the intensity of light incident on the layer.

Radiation absorber material can be uniformly disposed throughout theLTHC layer or can be non-homogeneously distributed. For example, asdescribed in U.S. Pat. No. 6,228,555, non-homogeneous LTHC layers can beused to control temperature profiles in donor elements. This can giverise to donor sheets that have improved transfer properties (e.g.,better fidelity between the intended transfer patterns and actualtransfer patterns).

Suitable radiation absorbing materials can include, for example, dyes(e.g., visible dyes, ultraviolet dyes, infrared dyes, fluorescent dyes,and radiation-polarizing dyes), pigments, metals, metal compounds, metalfilms, and other suitable absorbing materials. Examples of suitableradiation absorbers includes carbon black, metal oxides, and metalsulfides. One example of a suitable LTHC layer can include a pigment,such as carbon black, and a binder, such as an organic polymer. Anothersuitable LTHC layer includes metal or metal/metal oxide formed as a thinfilm, for example, black aluminum (i.e., a partially oxidized aluminumhaving a black visual appearance). Metallic and metal compound films maybe formed by techniques, such as, for example, sputtering andevaporative deposition. Particulate coatings may be formed using abinder and any suitable dry or wet coating techniques. LTHC layers canalso be formed by combining two or more LTHC layers containing similaror dissimilar materials. For example, an LTHC layer can be formed byvapor depositing a thin layer of black aluminum over a coating thatcontains carbon black disposed in a binder.

Dyes suitable for use as radiation absorbers in a LTHC layer may bepresent in particulate form, dissolved in a binder material, or at leastpartially dispersed in a binder material. When dispersed particulateradiation absorbers are used, the particle size can be, at least in someinstances, about 10 μm or less, and may be about 1 μm or less. Suitabledyes include those dyes that absorb in the IR region of the spectrum. Aspecific dye may be chosen based on factors such as, solubility in, andcompatibility with, a specific binder or coating solvent, as well as thewavelength range of absorption.

Pigmentary materials may also be used in the LTHC layer as radiationabsorbers. Examples of suitable pigments include carbon black andgraphite, as well as phthalocyanines, nickel dithiolenes, and otherpigments described in U.S. Pat. Nos. 5,166,024 and 5,351,617.Additionally, black azo pigments based on copper or chromium complexesof, for example, pyrazolone yellow, dianisidine red, and nickel azoyellow can be useful. Inorganic pigments can also be used, including,for example, oxides and sulfides of metals such as aluminum, bismuth,tin, indium, zinc, titanium, chromium, molybdenum, tungsten, cobalt,iridium, nickel, palladium, platinum, copper, silver, gold, zirconium,iron, lead, and tellurium. Metal borides, carbides, nitrides,carbonitrides, bronze-structured oxides, and oxides structurally relatedto the bronze family (e.g., WO_(2.9)) may also be used.

Metal radiation absorbers may be used, either in the form of particles,as described for instance in U.S. Pat. No. 4,252,671, or as films, asdisclosed in U.S. Pat. No. 5,256,506. Suitable metals include, forexample, aluminum, bismuth, tin, indium, tellurium and zinc.

Suitable binders for use in the LTHC layer include film-formingpolymers, such as, for example, phenolic resins (e.g., novolak andresole resins), polyvinyl butyral resins, polyvinyl acetates, polyvinylacetals, polyvinylidene chlorides, polyacrylates, cellulosic ethers andesters, nitrocelluloses, and polycarbonates. Suitable binders mayinclude monomers, oligomers, or polymers that have been, or can be,polymerized or crosslinked. Additives such as photoinitiators may alsobe included to facilitate crosslinking of the LTHC binder. In someembodiments, the binder is primarily formed using a coating ofcrosslinkable monomers or oligomers with optional polymer.

The inclusion of a thermoplastic resin (e.g., polymer) may improve, inat least some instances, the performance (e.g., transfer properties orcoatability) of the LTHC layer. It is thought that a thermoplastic resinmay improve the adhesion of the LTHC layer to the donor substrate. Inone embodiment, the binder includes 25 to 50 wt. % (excluding thesolvent when calculating weight percent) thermoplastic resin, and,preferably, 30 to 45 wt. % thermoplastic resin, although lower amountsof thermoplastic resin may be used (e.g., 1 to 15 wt. %). Thethermoplastic resin is typically chosen to be compatible (i.e., form aone-phase combination) with the other materials of the binder. In atleast some embodiments, a thermoplastic resin that has a solubilityparameter in the range of 9 to 13 (cal/cm³)^(1/2) (about 18 to 26(J/cm³)^(1/2)), preferably, 9.5 to 12 (cal/cm³)^(1/2) (about 19 to 24(J/cm³)^(1/2)), is chosen for the binder. Examples of suitablethermoplastic resins include polyacrylics, styrene-acrylic polymers andresins, and polyvinyl butyral.

Conventional coating aids, such as surfactants and dispersing agents,may be added to facilitate the coating process. The LTHC layer may becoated onto the donor substrate using a variety of coating methods knownin the art. A polymeric or organic LTHC layer can be coated, in at leastsome instances, to a thickness of 0.05 μm to 20 μm, preferably, 0.5 μmto 10 μm, and, more preferably, 1 μm to 7 μm. An inorganic LTHC layercan be coated, in at least some instances, to a thickness in the rangeof 0.0005 to 10 μm, and preferably, 0.001 to 1 μm.

Referring again to FIG. 2, an optional interlayer 216 may be disposedbetween the LTHC layer 214 and transfer layer 218. The interlayer can beused, for example, to minimize damage and contamination of thetransferred portion of the transfer layer and may also reduce distortionin the transferred portion of the transfer layer. The interlayer mayalso influence the adhesion of the transfer layer to the rest of thedonor sheet. Typically, the interlayer has high thermal resistance.Preferably, the interlayer does not distort or chemically decomposeunder the imaging conditions, particularly to an extent that renders thetransferred image non-functional. The interlayer typically remains incontact with the LTHC layer during the transfer process and is notsubstantially transferred with the transfer layer.

Suitable interlayers include, for example, polymer films, metal layers(e.g., vapor deposited metal layers), inorganic layers (e.g., sol-geldeposited layers and vapor deposited layers of inorganic oxides (e.g.,silica, titania, and other metal oxides)), and organic/inorganiccomposite layers. Organic materials suitable as interlayer materialsinclude both thermoset and thermoplastic materials. Suitable thermosetmaterials include resins that may be crosslinked by heat, radiation, orchemical treatment including, but not limited to, crosslinked orcrosslinkable polyacrylates, polymethacrylates, polyesters, epoxies, andpolyurethanes. The thermoset materials may be coated onto the LTHC layeras, for example, thermoplastic precursors and subsequently crosslinkedto form a crosslinked interlayer.

Suitable thermoplastic materials include, for example, polyacrylates,polymethacrylates, polystyrenes, polyurethanes, polysulfones,polyesters, and polyimides. These thermoplastic organic materials may beapplied via conventional coating techniques (for example, solventcoating, spray coating, die coating, or extrusion coating). Typically,the glass transition temperature (T_(g)) of thermoplastic materialssuitable for use in the interlayer is 25° C. or greater, preferably 50°C. or greater. In some embodiments, the interlayer includes athermoplastic material that has a T_(g) greater than any temperatureattained in the transfer layer during imaging. The interlayer may beeither transmissive, absorbing, reflective, or some combination thereof,at the imaging radiation wavelength.

Inorganic materials suitable as interlayer materials include, forexample, metals, metal oxides, metal sulfides, and inorganic carboncoatings, including those materials that are highly transmissive orreflective at the imaging light wavelength. These materials may beapplied to the light-to-heat-conversion layer via conventionaltechniques (e.g., vacuum sputtering, vacuum evaporation, or plasma jetdeposition).

The interlayer may provide a number of benefits. The interlayer may be abarrier against the transfer of material from the light-to-heatconversion layer. It may also modulate the temperature attained in thetransfer layer so that thermally unstable materials can be transferred.For example, the interlayer can act as a thermal diffuser to control thetemperature at the interface between the interlayer and the transferlayer relative to the temperature attained in the LTHC layer. This mayimprove the quality (i.e., surface roughness, edge roughness, etc.) ofthe transferred layer. The presence of an interlayer may also result inimproved plastic memory in the transferred material.

The interlayer may contain additives, including, for example,photoinitiators, surfactants, pigments, plasticizers, and coating aids.The thickness of the interlayer may depend on factors such as, forexample, the material of the interlayer, the material and properties ofthe LTHC layer, the material and properties of the transfer layer, thewavelength of the imaging radiation, and the duration of exposure of thedonor sheet to imaging radiation. For polymer interlayers, the thicknessof the interlayer typically is in the range of 0.05 μm to 10 μm. Forinorganic interlayers (e.g., metal or metal compound interlayers), thethickness of the interlayer typically is in the range of 0.005 μm to 10μm.

Referring again to FIG. 2, a thermal transfer layer 218 is included indonor sheet 200. Transfer layer 218 can include any suitable material ormaterials, disposed in one or more layers, alone or in combination withother materials. Transfer layer 218 is capable of being selectivelytransferred as a unit or in portions by any suitable transfer mechanismwhen the donor element is exposed to direct heating or to imagingradiation that can be absorbed by light-to-heat converter material andconverted into heat.

The present invention contemplates a transfer layer that includes a LEPas the light emitting material. One way of providing the transfer layeris by solution coating the light emitting material onto the donor. Inthis method, the light emitting material can be solubilized by additionof a suitable compatible solvent, and coated onto the donor sheet byspin-coating, gravure coating, Mayer rod coating, knife coating, diecoating, and the like. The solvent chosen preferably does notundesirably interact with (e.g., swell or dissolve) any of the alreadyexisting layers in the donor sheet. The coating can then be annealed andthe solvent evaporated to leave a transfer.

The transfer layer can then be selectively thermally transferred fromthe donor element to a proximately located receptor substrate. There canbe, if desired, more than one transfer layer so that a multilayerconstruction is transferred using a single donor sheet. The receptorsubstrate may be any item suitable for a particular applicationincluding, but not limited to, glass, transparent films, reflectivefilms, metals, semiconductors, and plastics. For example, receptorsubstrates may be any type of substrate or display element suitable fordisplay applications. Receptor substrates suitable for use in displayssuch as liquid crystal displays or emissive displays include rigid orflexible substrates that are substantially transmissive to visiblelight. Examples of suitable rigid receptors include glass and rigidplastic that are coated or patterned with indium tin oxide or arecircuitized with low temperature polysilicon (LTPS) or other transistorstructures, including organic transistors.

Suitable flexible substrates include substantially clear andtransmissive polymer films, reflective films, transflective films,polarizing films, multilayer optical films, and the like. Flexiblesubstrates can also be coated or patterned with electrode materials ortransistors, for example transistor arrays formed directly on theflexible substrate or transferred to the flexible substrate after beingformed on a temporary carrier substrate. Suitable polymer substratesinclude polyester substrates (e.g., polyethylene terephthalate,polyethylene naphthalate), polycarbonate substrates, polyolefinsubstrates, polyvinyl substrates (e.g., polyvinyl chloride,polyvinylidene chloride, polyvinyl acetals, etc.), cellulose estersubstrates (e.g., cellulose triacetate, cellulose acetate), and otherconventional polymeric films used as supports. For making OELs onplastic substrates, it is often desirable to include a barrier film orcoating on one or both surfaces of the plastic substrate to protect theorganic light emitting devices and their electrodes from exposure toundesired levels of water, oxygen, and the like.

Receptor substrates can be pre-patterned with any one or more ofelectrodes, transistors, capacitors, insulator ribs, spacers, colorfilters, black matrix, hole transport layers, electron transport layers,and other elements useful for electronic displays or other devices.

The present invention contemplates light emitting OEL displays anddevices. In one embodiment, OEL displays can be made that emit light andthat have adjacent devices that can emit light having different color.For example, FIG. 3 shows an OEL display 300 that includes a pluralityof OEL devices 310 disposed on a substrate 320. Adjacent devices 310 canbe made to emit different colors of light.

The separation shown between devices 310 is for illustrative purposesonly. Adjacent devices may be separated, in contact, overlapping, etc.,or different combinations of these in more than one direction on thedisplay substrate. For example, a pattern of parallel stripedtransparent conductive anodes can be formed on the substrate followed bya striped pattern of a hole transport material and a striped repeatingpattern of red, green, and blue light emitting LEP layers, followed by astriped pattern of cathodes, the cathode stripes oriented perpendicularto the anode stripes. Such a construction may be suitable for formingpassive matrix displays. In other embodiments, transparent conductiveanode pads can be provided in a two-dimensional pattern on the substrateand associated with addressing electronics such as one or moretransistors, capacitors, etc., such as are suitable for making activematrix displays. Other layers, including the light emitting layer(s) canthen be coated or deposited as a single layer or can be patterned (e.g.,parallel stripes, two-dimensional pattern commensurate with the anodes,etc.) over the anodes or electronic devices. Any other suitableconstruction is also contemplated by the present invention.

In one embodiment, display 300 can be a multiple color display. As such,it may be desirable to position optional polarizer 330 between the lightemitting devices and a viewer, for example to enhance the contrast ofthe display. In exemplary embodiments, each of the devices 310 emitslight. There are many displays and devices constructions covered by thegeneral construction illustrated in FIG. 3. Some of those constructionsare discussed as follows.

OEL backlights can include emissive layers. Constructions can includebare or circuitized substrates, anodes, cathodes, hole transport layers,electron transport layers, hole injection layers, electron injectionlayers, emissive layers, color changing layers, and other layers andmaterials suitable in OEL devices. Constructions can also includepolarizers, diffusers, light guides, lenses, light control films,brightness enhancement films, and the like. Applications include whiteor single color large area single pixel lamps, for example where anemissive material is provided by thermal stamp transfer, laminationtransfer, resistive head thermal printing, or the like; white or singlecolor large area single electrode pair lamps that have a large number ofclosely spaced emissive layers patterned by laser induced thermaltransfer; and tunable color multiple electrode large area lamps.

Low resolution OEL displays can include emissive layers. Constructionscan include bare or circuitized substrates, anodes, cathodes, holetransport layers, electron transport layers, hole injection layers,electron injection layers, emissive layers, color changing layers, andother layers and materials suitable in OEL devices. Constructions canalso include polarizers, diffusers, light guides, lenses, light controlfilms, brightness enhancement films, and the like. Applications includegraphic indicator lamps (e.g., icons); segmented alphanumeric displays(e.g., appliance time indicators); small monochrome passive or activematrix displays; small monochrome passive or active matrix displays plusgraphic indicator lamps as part of an integrated display (e.g., cellphone displays); large area pixel display tiles (e.g., a plurality ofmodules, or tiles, each having a relatively small number of pixels),such as may be suitable for outdoor display used; and security displayapplications.

High resolution OEL displays can include emissive layers. Constructionscan include bare or circuitized substrates, anodes, cathodes, holetransport layers, electron transport layers, hole injection layers,electron injection layers, emissive layers, color changing layers, andother layers and materials suitable in OEL devices. Constructions canalso include polarizers, diffusers, light guides, lenses, light controlfilms, brightness enhancement films, and the like. Applications includeactive or passive matrix multicolor or full color displays; active orpassive matrix multicolor or full color displays plus segmented orgraphic indicator lamps (e.g., laser induced transfer of high resolutiondevices plus thermal hot stamp of icons on the same substrate); andsecurity display applications.

EXAMPLES

Unless otherwise indicated, the chemicals used in the following Examplescan be obtained from Aldrich Chemical Co., Milwaukee, Wis.Tetrakis(triphenylphosphine) palladium(b 0) andbis(1,5-cyclooctadiene)nickel(0) are available from Strem Chemicals,Inc., Newburyport, Mass.4,4,5,5-Tetramethyl-2-phenyl-1,3,2-dioxaborolane can be preparedaccording to Ishiyama et al., Tetrahedron Lett., 1997, 3447-3450,incorporated herein by reference.

Example 1 Synthesis of 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane (18)

1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane (18) was prepared followingprocedures outlined in J. Org. Chem 45, 1156 (1980), incorporated hereinby reference.

p-Bromophenol (186.8 g) and sodium hydroxide (43.2 g) were added to 325mL of dimethyl sulfoxide (DMSO) and stirred at 60° C. for 2 hrs undernitrogen. 1,2,-Bis(2-chloroethoxy)ethane (45.09 g) in 108 mL of degassedDMSO was then added drop wise at 60° C. The resulting mixture was heatedto 90° C. overnight, cooled to room temperature, and mixed with 2 litersof water to yield a pale brown precipitate that was isolated byfiltration, and recrystallized from methanol to give 85 grams (95%yield) of the desired product as determined by ¹H-NMR.

Example 2 Synthesis of 4,7-Dibromobenzo[1,2,5]thiadiazole (19)

4,7-Dibromobenzo[1,2,5]thiadiazole (19) was made as outlined in J.Heterocycl. Chem. 7, 629- 633 (1970), incorporated herein by reference.

Example 3 Synthesis of9,9-Dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene(20)

9,9-Dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene(20) was made according to Chem. Commun., 1997, 1597-1598, incorporatedherein by reference.

Example 4 Synthesis of 9,9-dioctyl-2,7-dibromo-fluorene (21)

9,9-Dioctyl-2,7-dibromo-fluorene (21) was made according to Can. J.Chem. 1998, 1571-1577, incorporated herein by reference.

Example 5 Synthesis of2,7-dibromo-9,9-bis(3,6-dioxahexyl-6-phenyl)-fluorene (22)

2,7-Dibromo-9,9-bis(3,6-dioxahexyl-6-phenyl)-fluorene (22) wassynthesized from PhO(CH₂)₂O(CH₂)₂I and 2,7-dibromofluorene following thegeneral procedure as demonstrated in the synthesis of2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene(23) as described inExample 6.

Example 6 Synthesis of 2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene(23)

Benzyltriethylammonium chloride (3.19 g, 14 mmole, 0.077 equiv.) and2,7-dibromofluorene (59 g, 182 mmole, 1 equiv.) were suspended in 178 mLDMSO. 50% aqueous NaOH (80 mL) was added.1-Bromo-2-(2-methoxyethoxy)ethane (80 g, 437 mmole, 2.4 equiv.) was thenadded in small portions. The reaction was stirred at room temperaturefor 2 hours before it was stopped and the aqueous layer was extractedwith ether. The combined ether layers were washed with water five timesand dried over Na₂SO₄. The organic layer was filtered, evaporated todryness and the residue was flash chromatographed on a silica-gel columnto give the pure compound 23 (73 g), in a yield of 86%. The structurewas confirmed by ¹H NMR.

Example 7 Preparation of Blue Emitting Mw=7K poly(9,9-dioctylfluorene)Oligomer with Reactive Boralane End Groups (24-26)

9,9-Dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene(21)(9.63 g, 15 mmole, 1 equiv.) and 9,9-dioctyl-2,7-dibromo-fluorene(20) (5.75 g, 10.5 mmole, 0.7 equiv.) were mixed together with Aliquat®336 (1.51 g, 3.75 mmole, 0.25 equiv.) in toluene (68 mL). 2 M Na₂CO₃aqueous solution (23.4 mL) was added to the suspension and thesuspension then degassed with nitrogen for half an hour.Tetrakis(triphenylphosphine) palladium(0) (73 mg, 0.063 mmole, 0.0042equiv.) was then added to the mixture and the reaction then heated toreflux under nitrogen for 1 day. The reaction mixture was cooled down toroom temperature and poured into a 500 mL methanol:water (9:1) mixture.The precipitate was purified by repeated dissolution in THF andprecipitation in methanol. The product (24) was obtained as a lightyellow powder (9.0 g, 100% yield). Gel permeation chromatography (GPC)analysis shows Mw 7,739 Daltons and Mn 3,880 Daltons and polydispersity(PD) of 1.99.

A similar procedure as in preparation of 24 was carried out (expect that2 g ammonium acetate (NH₄Ac) was used in the 9:1 methanol/water mixture)to give compound 25 (7.4 g). Gel permeation chromatography analysisshows Mw 8,770 Daltons, Mn 4,590 Daltons and polydispersity of 1.91.

The same procedure as in the preparation of 25 was carried out with9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene(21) (30 g) and 9,9-dioctyl-2,7-dibromo-fluorene (21) (17.9 g), Aliquat®336 (4.72 g), toluene (212 mL), 2 M Na₂CO₃ aqueous solution (73 mL) andtetrakis(triphenylphosphine) palladium(0) (0.226 g) to give compound 26(27 g). Gel permeation chromatography analysis shows Mw 8,130 Daltons,Mn 4,440 Daltons and polydispersity of 1.83.

Example 8 Preparation of Green Emitting Mw=7Kpoly(9,9-dioctylfluorene-co-benzthiadiazole) Oligomer with ReactiveBoralane End Groups (27-29)

9,9-Dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene20 (9.63 g, 15 mmole, 1 equiv.) and 4,7-dibromo-2,1,3-benzothiadiazole19 (3.087 g, 10.5 mmole, 0.7 equiv.) were mixed together with Aliquat®336 (1.51 g, 3.75 mmole, 0.25 equiv.) in toluene (68 mL). 2 M Na₂CO₃aqueous solution (23.4 mL) was added to the suspension and thesuspension then degassed with nitrogen for half an hour.Tetrakis(triphenylphosphine) palladium (0) (73 mg, 0.063 mmole, 0.0042equiv.) was then added to the mixture and the reaction then heated toreflux under nitrogen for 1 day. After the reaction mixture was cooleddown to room temperature, it was poured into a 500 mL methanol: water(9:1) mixture. The precipitate was redissolved in 80 mL chloroform andpoured into 300 mL methanol. The product (27) was obtained as a yellowpowder (3.5 g, 64%). Gel permeation chromatography analysis shows Mw7,290 Daltons, Mn 4,040 Daltons and polydispersity of 1.80.

A similar procedure as in preparation of 27 was carried out (expect that2 g NH₄Ac was used in the 9:1 methanol/water mixture) to give compound28 (7.4 g). Gel permeation chromatography analysis shows Mw 6,040Daltons, Mn 3,580 Daltons and polydispersity of 1.69.

The same procedure as in preparation of 28 was carried out with9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene20 (35 g) and 4,7-dibromo-2,1,3-benzothiadiazole 19 (11.2 g), Aliquat®336 (5.5 g), toluene (247 mL), 2 M Na₂CO₃ aqueous solution (85 mL) andtetrakis(triphenylphosphine) palladium(0) (0.264 g) to give compound 29(26 g). Gel permeation chromatography analysis shows Mw 5,930 Daltons,Mn 3,250 Daltons and polydispersity of 1.82.

Example 9 Synthesis of Soft Segment End-Capped Poly(9,9-dioctylfluorene)Oligomer

In a glove box, a 500 mL round-bottomed flask fitted with a magneticstir bar and rubber septa was charged with 3.90 g (0.025 mole)2,2′-bipyridyl and 6.87 g(0.025 mole) bis(1,5-cyclooctadiene)nickel(0).The sealed flask was transferred to a fume hood and 75 mL dry tolueneand 30 mL DMF added via cannula. The sealed flask was heated at 80° C.in an oil bath for 30 min. A solution of 0.50 g (0.0011 mole)1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane 18, 0.45 g (0.0028 mole)bromobenzene and 5.36 g (0.0098 mole) 2,7-dibromo-9,9-dioctylfluorene 21in about 30 mL toluene was added via cannula. The sealed flask washeated for five minutes followed by the addition of 1.41 g (0.013 mole)1,5-cyclooctadiene. Stirring was continued for 16 hours at 80° C.

The warm reaction mixture was stirred with 50 mL of concentrated HCl,diluted with an equal volume of water and then stirred for an additional30 min. Attempted extraction with THF gave a 3-phased system. The mostupper phase was removed and was added to an excess of methanol to give aprecipitate. This was collected by filtration and dried to give, by GPC,Mw 8,760 Daltons, Mn 4,420 Daltons, PD 1.98. The proton NMR gave signalsat 3.82, 3.95 and 4.25 which when compared to a multiplet at 2.10 (CH₂adjacent to fluorene C-9 position) suggested 8.85 mole % incorporationof 1,2-bis[β, β′-(p-bromophenoxy)ethoxy]ethane. Based on thisstoichiometry we assume that the poly(9,9-dioctylfluorene) oligomer wasterminated with the polyether capping group.

Example 10 Preparation of Soft Segment End Capped Blue EmittingPoly(9,9-dioctylfluorene) Oligomer (30)

Into a 500 mL flask fitted with a reflux condenser, nitrogen bubbler andthermocouple were combined 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane(18) (0.874 g, 1.90 mmoles), 2.18 g blue oligomer 25 (0.475 mmoles),sodium carbonate (9.0 ml of 2M, 18 mmoles), Aliquat® 336 (0.20 g, 0.5mmoles) and 34 mL of toluene. The content was degassed using a stream ofnitrogen for 1 hour. The mixture was heated at reflux for 30 minutesfollowed by the addition of 0.01 g tetrakis(triphenylphosphine)palladium(0). Refluxing was continued for 2 days followed by cooling toroom temperature. The content of the flask was slowly poured into amixture of 500 mL methanol/50 mL water with vigorous stirring and thesolid obtained then collected by filtration. The solid was dissolved in75 ml of chloroform and slowly poured into 500 mL methanol with vigorousstirring and the precipitate collected by filtration and washed with 300mL methanol and air dried.

Using the above apparatus and the same Suzuki coupling reagents, thedried polymer in 33 mL toluene was phenyl capped using4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane (0.5 g). The cooledreaction mixture was slowly poured into a mixture of 400 mL methanol/50mL water with vigorous stirring and the solid collected by filtrationand dissolved in 50 ml of chloroform. The solution was passed through asmall pad of silica gel on a course glass frit, the silica gel rinsedwith 50 mL of chloroform and chloroform solutions combined, by pouringvery slowly into 400 mL methanol with vigorous stirring. The solutionwas cloudy and contained no filterables. Concentration of the mixture byrotary evaporation precipitated a finely divided solid. This wascollected and washed with 300 mL methanol and air drying gave 0.49 g ofether capped blue oligomer 30. Gel permeation chromatography analysisshowed Mw 17,000 Daltons and Mn 7,230 Daltons and polydispersity of 2.4.

Example 11 Preparation of Soft Segment End Capped Green EmittingPoly(9,9-dioctylfluorene-co-benzthiadiazole) Oligomer (31)

Into a 500 mL flask fitted with a reflux condenser, nitrogen bubbler andthermocouple were combined 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane(18) (2.0134 g, 4.37 mmoles), 3.5 g green oligomer 27 (0.875 mmoles),sodium carbonate (16.5ml at 2M, 33 mmoles), Aliquat® 336 (0.35 g, 0.9mmoles) and 54 ml of toluene. The content was degassed using a stream ofnitrogen for 1 hour. The mixture was heated at reflux for 30 minutesfollowed by the addition of 0.01 g tetrakis(triphenylphosphine)palladium(0). Refluxing was continued for 2 days followed by cooling toroom temperature. The content of the flask was slowly poured into amixture of 400mL methanol/50 mL water with vigorous stirring and thesolid obtained then collected by filtration. The solid was dissolved in20 mL of chloroform, passed through a small pad of silica gel and thesilica gel then rinsed with 50 mL more chloroform. The combinedchloroform solutions were slowly poured into 500 mL methanol withvigorous stirring and the precipitate collected by filtration and washedwith 200 mL methanol and air dried.

Using the above apparatus and the same Suzuki coupling reagents, thedried polymer in 54 mL toluene was phenyl capped using4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane (1.0 g). The cooledreaction mixture was slowly poured into a mixture of 400 mL methanol/50mL water with vigorous stirring and the solid collected by filtrationand dissolved in 50 mL of chloroform. The solution was passed through asmall pad of silica gel on a course glass frit, the silica gel rinsedwith 50 mL of chloroform and chloroform solutions combined. Pouring veryslowly into 400 mL methanol with vigorous stirring, collecting the solidby filtration, washing this with 300ml methanol and air drying gave 1.26g of ether capped green oligomer 31.

Example 12 Preparation of Fluorenyl TerminatedPoly(9,9-bis(3,6-dioxaheptyl)-fluorene) (32)

A Shlenk tube was charged with2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene 23 (2.64 g, 5.0 mmole),triphenyl phosphine (0.786 g, 3 mmole), zinc dust (1.07 g, 16.5 mmole),dipyridyl (0.156 g, 1 mmole), nickel bromide (0.218 g, 1 mmole),2-bromo-fluorene (32 mg, 0.13 mmole), anhydrous toluene (15 mL) andanhydrous dimethyl formamide (DMF) (15 mL) under nitrogen. The reactionwas heated at 80° C. for 4 days. After the reaction was cooled down, itwas poured into methanol (60 mL). Concentrated HCl (5 mL) was then addedand the mixture was stirred overnight to give a light yellow mass, whichwas collected by filtration. The mass was dissolved in tetrahydrofuran(THF) and precipitated from water to give 1.6 g of yellow powder in ayield of 87% polymer 32. Gel permeation chromatography analysis shows Mw39,600 Daltons and Mn 8,480 Daltons and polydispersity of 4.67. DSCanalysis gave Tg=82.6° C.

Example 13 Preparation of Phenyl TerminatedPoly[(9,9-bis(3,6-dioxaheptyl)-fluorene)-co-(9,9-dioctylfluorene)] (33)

9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene 20 (3.21 g, 5 mmole, 1 equiv.) and2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene 23 (2.38 g, 4.5 mmole, 0.9equiv.) were mixed together with Aliquat® 336 (0.51 g, 1.25 mmole, 0.25equiv.) in toluene (50 mL). 2 M Na₂CO₃ aqueous solution (8.6 mL) wasadded to the suspension and the suspension then degassed with nitrogenfor half an hour. Tetrakis(triphenylphosphine) palladium(0) (24 mg,0.021 mmole, 0.0042 equiv.) was then added to the mixture. The reactionwas heated to reflux under nitrogen for three days. Phenyl bromide (0.5g, 3.18 mmole) was added and the reaction then refluxed for another day.After the reaction mixture was cooled down to room temperature, it waspoured into a 500 mL methanol: water (9:1) mixture. The precipitate waspurified by repeated dissolution in THF and precipitation into methanol.The product (polymer 33) was obtained as a light yellow powder (3.04 g)in a yield of 89%. This polymer comprises 50%9,9-bis(3,6-dioxaheptyl)-fluorene) units (BDOH) and 50%9,9-dioctylfluorene units. Gel permeation chromatography analysis showsMw 27,800 Daltons and Mn 8,370 Daltons and polydispersity of 3.33. DSCanalysis gave Tg=64.6° C., Tc=100.7° C., Tm=145.1° C.

Example 14 Preparation of 25 Mole % BDOH Phenyl TerminatedPoly[(9,9-bis(3,6-dioxaheptyl)-fluorene)-co-(9,9-dioctylfluorene)] (34)

The procedure used in Example 13 was repeated using2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene 23 (1.19 g, 2.25 mmole,0.45 equiv.),9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene20 (3.21 g, 5 mmole, 5 equiv.), 9,9-dioctyl-2,7-dibromo-fluorene 21(1.21 g, 2.25 mmole, 0.45 equiv.), Aliquat® 336 (0.51 g, 1.25 mmole,0.25 equiv.) and tetrakis(triphenylphosphine) palladium(0) (24 mg, 0.021mmole, 0.0042 equiv.) in toluene (50 mL). The product (polymer 34) wasobtained as a light green-yellow solid (3.1 g) in a yield of 91%. Thispolymer comprises 25% 9,9-bis(3,6-dioxaheptyl)-fluorene) units (BDOH)and 75% 9,9-dioctylfluorene units. Gel permeation chromatographyanalysis shows Mw 27,400 Daltons and Mn 8,110 Daltons and polydispersityof 3.38. DSC analysis gave Tg=57.5° C., Tc=103.6° C., Tm=136.6° C.

Example 15 Preparation of 10 Mole % BDOH Phenyl TerminatedPoly[(9,9-bis(3,6-dioxaheptyl)-fluorene)-co-(9,9-dioctylfluorene)] (35)

The procedure used in Example 13 was repeated with2,7-dibromo-9,9-bis(3,6-dioxaheptyl)-fluorene 23 (0.48 g, 0.9 mmole,0.18 equiv.),9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-fluorene20 (3.21 g, 5 mmole, 1 equiv.), 9,9-dioctyl-2,7-dibromo-fluorene 21(1.97 g, 3.6 mmole, 0.72 equiv.), Aliquat® 336 (0.51 g, 1.25 mmole, 0.25equiv.) and tetrakis(triphenylphosphine) palladium(0) (24 mg, 0.021mmole, 0.0042 equiv.) in toluene 50 mL. The product (polymer 35) wasobtained as a light green-yellow solid 2.9 g in a yield of 85%. Thispolymer comprises 10% 9,9-bis(3,6-dioxaheptyl)-fluorene) units (BDOH)and 90% 9,9-dioctylfluorene units. Gel permeation chromatographyanalysis shows Mw 29,300 Daltons and Mn 9,760 Daltons and polydispersityof 3.01. DSC analysis gave Tg=54.1° C., Tc=92.1° C., Tm=130.8° C.

Example 16 Preparation of 25 Mole % BDOHP Phenyl TerminatedPoly[(9,9-bis(3,6-dioxahexyl-6-phenyl)-fluorene)-co-(9,9-dioctylfluorene)](36)

The procedure used in Example 13 was repeated with2,7-dibromo-9,9-bis(3,6-dioxahexyl-6-phenyl)fluorene 22 (4.0 g, 6.13mmole, 0.45 equiv.),9,9-dioctyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)fluorene20 (8.75 g, 13.62 mmole, 1 equiv.), 9,9-dioctyl-2,7-dibromofluorene 21(3.36 g, 6.13 mmole, 0.45 equiv.), Aliquat® 336 (0.51 g, 1.25 mmole,0.25 equiv.) and tetrakis(triphenylphosphine) palladium (0) (79 mg,0.068 mmole, 0.005 equiv.) in toluene (140 mL). The product (polymer 36)was obtained as a light green solid (11.5 g) in a yield of 90%. Thispolymer comprises 10% 9,9-bis(3,6-dioxahexyl-6-phenyl)fluorene) units(BDOHP) and 90% 9,9-dioctylfluorene units. Gel permeation chromatographyanalysis shows Mw 20,300 Daltons and Mn 7,770 Daltons and polydispersityof 2.61. 0.2 mg of the compound in 1 mL of toluene gave violet emissionat λmax of 416 nm, and 435 nm(sh). DSC analysis gave Tg=50° C., Tc=91°C., Tm=155° C.

Example 17 Preparation of Green Emitting Block Copolymer (37, 38)

Into a 500 mL flask fitted with a reflux condenser, nitrogen bubbler andthermocouple were combined 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane(18) (0.9912 g, 2.154 mmoles), 3.5 g green oligomer 29 (1.9800 mmoles),sodium carbonate (37 ML of 2M solution, 75 mmoles), Aliquat® 336 (0.80g, 2.0 mmoles) and 74 ml of toluene. The content was degassed using astream of nitrogen for 1 hour. The mixture was heated at reflux for 30minutes followed by the addition of 0.02 g oftetrakis(triphenylphosphine) palladium(0). Refluxing was continued for 3days followed by cooling to room temperature. The content of the flaskwas slowly poured into a mixture of 500 mL methanol/50 mL water withvigorous stirring and the solid obtained then collected by filtration.The solid was dissolved in 75 mL of chloroform, passed through a smallpad of silica gel and the silica gel then rinsed with 50 mL morechloroform. The combined chloroform solutions were slowly poured into750 mL methanol with vigorous stirring and the precipitate collected byfiltration and washed with 200 mL methanol and air-dried.

Using the above apparatus and the same Suzuki coupling reagents, thedried polymer in 74 mL toluene was phenyl capped using4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane (1.0 g) for two days.The organic layer was separated and slowly poured into a mixture of 500mL methanol/50 mL water with vigorous stirring and the solid collectedby filtration and dissolved in 75 mL of chloroform. The solution waspassed through a small pad of silica gel on a course glass frit, thesilica gel rinsed with 50 mL of chloroform and the chloroform solutionscombined, by pouring very slowly into 750 mL methanol with vigorousstirring, collecting the solid by filtration, washing this with 200 mlmethanol and air drying gave 3.2 g of ether capped green hard/softsegment polymer 37. Gel permeation chromatography analysis shows Mw81,100 Daltons and Mn 26,000 Daltons and polydispersity of 3.12.

Preparation of green/soft segment polyfluorene 38: By adoption of thegeneral method for the synthesis and isolation of the polymer 37, thereaction of 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane (18) (0.949 g,2.0632 mmoles), green oligomer 29 (4.8824 g, 2.0084 mmoles), sodiumcarbonate (38 mL of 2M solution, 76 mmoles) and Aliquat® 336 (0.80 g,2.0 mmoles) in 74 ml of toluene gave the corresponding bromineterminated green/soft segment polyfluorene 38. Capping with 1.0 g of4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane in toluene under Suzukicoupling conditions as specified for polymer 37 gave 3.55 g of polymer38. Gel permeation chromatography analysis shows Mw 104,000 Daltons andMn 30,400 Daltons and polydispersity of 3.43.

Example 18 Preparation of Blue Emitting Block Copolymer (39, 40)

By adoption of the general method for the synthesis and isolation of thepolymer 37, the reaction of 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane(18) (0.8078 g, 1.7555 mmoles), blue oligomer 26 (4.8512 g, 1.5895mmoles), sodium carbonate (30 mL of 2M solution, 60 mmoles) and Aliquat®336 (0.60 g, 1.60 mmoles) in 75 ml of toluene gave the correspondingbromine terminated blue/soft segment polyfluorene 39. Capping with 1.0 gof 4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane in 75 mL tolueneunder Suzuki coupling conditions as specified for polymer 37, gave 2.8 gof polymer 39. Gel permeation chromatography analysis shows Mw 81,700Daltons and Mn 32,100 Daltons and polydispersity of 2.55.

Preparation of blue/soft segment polyfluorene 40: By adoption of thegeneral method for the synthesis and isolation of the polymer 37, thereaction of 1,2-bis[β,β′-(p-bromophenoxy)ethoxy]ethane (18) (0.7642 g,1.66075 mmoles), blue oligomer 26 (4.9009 g, 1.6058 mmoles), sodiumcarbonate (30 mL of 2M solution, 60 mmoles) and Aliquat® 336 (0.60 g,1.60 mmoles) in 75 ml of toluene gave the corresponding bromineterminated blue/soft segment polyfluorene 40. Capping with 1.0 g of4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane in 75 mL toluene underSuzuki coupling conditions as specified for polymer 37, gave 2.6 g ofpolymer 40. Gel permeation chromatography analysis shows Mw 102,000Daltons and Mn 40,700 Daltons and polydispersity of 2.51.

Example 19 Preparation of a Donor Sheet without a Transfer Layer

A thermal transfer donor sheet was prepared in the following manner. AnLTHC solution, given in Table I, was coated onto a 0.1 mm thickpolyethylene terephthalate (PET) film substrate (M7 from Teijin, Osaka,Japan). Coating was performed using a Yasui Seiki Lab Coater, ModelCAG-150, using a microgravure roll with 150 helical cells per inch. TheLTHC coating was in-line dried at 80° C. and cured under ultraviolet(UV) radiation. TABLE I LTHC Coating Solution Parts by Component TradeDesignation Weight carbon black pigment Raven 760 Ultra ⁽¹⁾ 3.55polyvinyl butyral resin Butvar B-98 ⁽²⁾ 0.63 acrylic resin Joncryl 67⁽³⁾ 1.90 Dispersant Disperbyk 161 ⁽⁴⁾ 0.32 Surfactant FC-430 ⁽⁵⁾ 0.01epoxy novolac acrylate Ebecryl 629 ⁽⁶⁾ 12.09 acrylic resin Elvacite 2669⁽⁷⁾ 8.06 2-benzyl-2-(dimethylamino)-1-(4- Irgacure 369 ⁽⁸⁾ 0.82(morpholinyl)phenyl)butanone 1-hydroxycyclohexyl phenyl ketone Irgacure184 ⁽⁸⁾ 0.12 2-butanone 45.31 1,2-propanediol monomethyl ether 27.19acetate⁽¹⁾ Columbian Chemicals Co., Atlanta, GA⁽²⁾ Solutia Inc., St. Louis, MO⁽³⁾ S. C. Johnson & Son, Inc. Racine, WI⁽⁴⁾ Byk-Chemie USA, Wallingford, CT⁽⁵⁾ Minnesota Mining and Manufacturing Co., St. Paul, MN (synthesizableaccording to Example 5 of U.S. Pat. No. 3,787,351)⁽⁶⁾ UCB Radcure Inc., N. Augusta, SC⁽⁷⁾ ICI Acrylics Inc., Memphis, TN⁽⁸⁾ Ciba-Geigi Corp., Tarrytown, NY

Next, an interlayer solution, given in Table II, was coated onto thecured LTHC layer by a rotogravure coating method using the Yasui Seikilab coater, Model CAG-150, with a microgravure roll having 180 helicalcells per lineal inch. This coating was in-line dried at 60° C. andcured under ultraviolet (UV) radiation. TABLE II Interlayer CoatingSolution PARTS BY COMPONENT WEIGHT SR 351 HP (trimethylolpropanetriacrylate 14.85 ester, available from Sartomer, Exton, PA) Butvar B-980.93 Joncryl 67 2.78 Irgacure 369 1.25 Irgacure 184 0.19 2-butanone48.00 1-methoxy-2-propanol 32.00

Example 20 Solution for Use on the Receptor

The following solution was prepared and coated on the receptorsubstrate: PEDT: PEDT (poly(3,4-ethylenedioxythiophene)) solution(CH-8000 from Bayer AG, Leverkusen, Germany, diluted 1:1 with deionizedwater) was filtered through a Whatman Puradisc™ 0.45 μm Polypropylene(PP) syringe filter.

Example 21 Preparation of the Receptor

Receptors consisting of unpatterned and patterned ITO on glass were usedfor LITI dosing evaluation and conventional lamp preparation,respectively. The patterned substrates were made using standardphotolithographic methods. The receptors were processed as follows: ITO(indium tin oxide) glass (Delta Technologies, Stillwater, Minn., lessthan 100 Ω/square, 1.1 mm thick) was ultrasonically cleaned in a hot, 3%solution of Deconex 12NS (Borer Chemie AG, Zuchwil, Switzerland). Thesubstrates were then placed in the Plasma Science plasma treater forsurface treatment under the following conditions:

-   -   Time: 2 minutes    -   Power: 500 watt (165 W/cm²)    -   Oxygen Flow: 100 sccm

Immediately after plasma treatment, the PEDT solution as described inExample 20 was filtered and dispensed through a Whatman Puradisc™ 0.45μm Polypropylene (PP) syringe filter onto the ITO substrate. Thesubstrate was then spun (Headway Research spincoater) at 2000 rpm for 30s yielding a PEDT film thickness of 40 nm. All of the substrates wereheated to 200° C. for 5 minutes under nitrogen. In addition, some of thePEDT coated substrates were plasma treated. In this case, the substratewas placed into the Plasma Sciences Plasma Tester under the followingconditions.

-   -   Time: 20 s    -   Power: 500W (165W/cm²)    -   Argon Flow: 20 sccm    -   Pressure: 125 mTorr

Example 22 Preparation of Solutions For Thermal Transfer Experiments

The following procedure was used to prepare solutions for thermaltransfer experiments: The polymeric materials from Examples 9, 10, 13,14, 15, 17, and 18 respectively were independently dissolved at 2 wt/wt% into toluene (HPLC grade obtained from Aldrich Chemical, Milwaukee,Wis.) by stirring for 1- 2 hours at room temperature. Each solution wasfiltered through a 0.45 μm polypropylene (PP) syringe filter beforeapplication.

Example 23 Preparation of Transfer Layers on Donor Sheet and LaserInduced Thermal Imaging of Transfer Layers

Transfer layers were formed on the donor sheets of Example 19. Thetransfer layers were disposed on the donor sheets by spinning (HeadwayResearch spincoater) at about 2000-2500 rpm for 30 s to yield a filmthickness of approximately 100 nm.

Donor sheets coated solutions as described above were brought intocontact with receptor substrates as prepared in Example 21. Next, thedonors were imaged using two single-mode Nd:YAG lasers. Scanning wasperformed using a system of linear galvanometers, with the combinedlaser beams focused onto the image plane using an f-theta scan lens aspart of a near-telecentric configuration. The laser energy density was0.4 to 0.8 J/cm². The laser spot size, measured at the l/e² intensity,was 30 micrometers by 350 micrometers. The linear laser spot velocitywas adjustable between 10 and 30 meters per second, measured at theimage plane. The laser spot was dithered perpendicular to the majordisplacement direction with about a 100 micrometer amplitude. Thetransfer layers were transferred as lines onto the receptor substrates,and the intended width of the lines was about 100 micrometers.

This example demonstrated that incorporation of polar poly(oxyalkylene)soft segments as capping groups, side chains, or internal soft segmentsin polyfluorene light emitting polymers can enhance thermal transfer ofpolyfluorenes to conducting ionic buffer layers such as PEDT. Polyethersegments were chosen because they are electro-inactive and because theyare solubility matched with PEDT buffer layers.

The polymers of Examples 9, 10, 13, 14, and 15 all transferred withoutdefect and with smooth edges to PEDT substrates and the polymers ofExamples 17 and 18 transfer with well defined lines that have breaks.Corresponding control samples involving poly(9,9-dioctyl-fluorene)homopolymers did not transfer as well to these substrates under similarconditions. It is thought, without wishing to be bound by any particulartheory, that this result may be explained by a solubility parametermismatch between poly(9,9-dioctyl-fluorene) (δ=16 J^(1/2)cm^(−3/2)) andPEDT (δ=23 J^(1/2)cm^(−3/2)). This mismatch is overcome by the additionof polar poly(oxyalkylene) soft segments in the new polymers of thisinvention. Hydrophilic polyether homopolymers are known to exhibitsolubility parameters in the range of δ=22 J^(1/2)cm^(−3/2) that willmatch well to PEDT.

Example 24 Preparation of OLED Devices

Electroluminescent devices were prepared as follows. The polymericmaterials of Examples 9, 10, 11, 13, 14, 15, 16, 17, and 18 wereindependently dissolved at 1-3 wt/wt % into toluene (HPLC grade obtainedfrom Aldrich Chemical, Milwaukee, Wis.) by stirring for 1-2 hours atroom temperature. In some cases, a hole transporting agent (HTA) such asTPD (N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)benzidine), NPB(N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1,1′-biphenyl-4,4′-diamine),or CBP (N,N′-dicarbazole-biphenyl) were added in a ratio ofpolymer/HTA=10:3. Each solution was filtered through a 0.45 μmpolypropylene (PP) syringe filter before application. These solutionswere spin coated onto PEDT coated ITO substrates. Cathodes were appliedby vapor depositing either 1 nm LiF/200 nm Al (polymers of Examples 9,10, 11, 13, 14, 15, and 16) or 40 nm calcium/400 nm silver (polymers ofExamples 17 and 18). In all cases, light was seen from the conventionallamps. The devices showed diode type behavior. The observed color isviolet (Examples 9 and 10), white (Example 13), blue-white (Example 14),blue (Examples 16 and 18), light blue (Example 15), and green (Examples11 and 17).

The present invention should not be considered limited to the particularexamples described above, but rather should be understood to cover allaspects of the invention as fairly set out in the attached claims.Various modifications, equivalent processes, as well as numerousstructures to which the present invention may be applicable will bereadily apparent to those of skill in the art to which the presentinvention is directed upon review of the instant specification.

Each of the patents, patent documents, and publications cited above ishereby incorporated into this document as if reproduced in full.

1. A donor sheet, comprising: a substrate; a light-to-heat conversionlayer; and a transfer layer comprising a light emitting polymercomprising a plurality of arylene monomeric units and a plurality ofsoft segment units independently selected from soft segment end caps;soft segment side chains coupled to a portion, but not all, of thearylene monomeric units; internal soft segment monomeric units; andcombinations thereof.
 2. The donor sheet of claim 1, wherein the lightemitting polymer comprises a polymer selected from one of Formulas I toXVII:

wherein D₁ and D₂ are substituted or unsubstituted arylene moieties,each EC is independently a soft segment end cap group, X and Y arecapping groups, Ar₁ and Ar₂ are independently selected from substitutedand unsubstituted C6-C20 arylene, substituted and unsubstituted C2-C20heteroarylene, and substituted and unsubstituted C18-C60 divalenttriarylamines, k, l, m, n, and o are integers in the range of 2 to 1000,q is an integer in the range of 1 to 4, each Z₁ is independently a softsegment side chain, and each T is independently a soft segment moiety.